Excessive Oil Use

[mikeb]

Thanks for that oilman, I did read that though on the website that Carlos Linked me too :D

Can you explain though why 5w40 dissapears quicker than 10w40?

The only explanation I have had is that it may seep past the rings quicker when the engine is cold. I think I'm right that when cold the 5w40 will be thinner? And when the engine is warm the rings will expand so the thickness when warm won't matter.

The above is only a theory but shows why I am reluctant to use a thinner oil from my past experience. I understand that for normal engines you are both perfectly correct. But my engine is "special" I also understand that long term damage could be occuring by using oil which is too thick.

I have looked into the price of having my rings done and the cheapest quote I got was around £500, Toyota said around £800+vat. This amount is unacceptable espicially when nowhere I have been can gaurantee if that is where the oil is going.

At the end of the day it will be as cheap to replace the engine in a few years (if I still have the car) - So long term damage isn't my greatest worry.

My greatest worry at the moment is ensuring that whilst doing a long trip (don't happen often) I don't run out of oil and do some immediate damage! So if 15w40 is going to stay in longer and protect the engine so it lasts another 50,000 miles then I would be happy. Where as 5w40 may be able to protect the engine better and make it last 100,000 miles but may cause premature engine failure through running out whilst doinga motorway trip.

Do you see where I'm coming from??

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That's pretty much the head and tail of it Sotal. But you can't know for sure that the consumption difference is purely the due to difference in viscosity, unless you compare the exact same oil but in a different grade. Cheap oil can break down quickly and go 'thin', then it will burn off quicker.

When I changed from 5w-40 semi synthetic to 0w-40 fully synthetic (but only hydrocracked), my engine burnt less oil. And the 0w-40 is on the low side of SAE40 too. I'm currently using Castrol RS 0w-40, primarily because Halford's have been selling it at half price (£17.50 for 4L, and I think the offer is on at the moment). It's by no means the best synthetic oil available, but for the discounted price I don't know of any better alternatives, unless Simon has any suggestions?

If I were in your situation (3k miles per gallon of oil wasn't it?), I would be inclined to just use a cheap thin oil (for max protection), or maybe a thick 15w-40 decent oil in the hope it will burn less of it when cold. There should be a chart in your handbook to show what grade of oil to use for the range of environmental temps, you may be able to get away with 15w-40.

I don't see the point in wasting expensive oil on it when it won't hang around for long enough to break down. The only way to cure it is to swap/rebuild your engine, either now or if it goes wrong. And it seems the 7a-fe is a renowned oil burner, plus it's hardly a high performance engine (certainly won't see the high temps of a turbo motor), so even if you do swap/rebuild it you might not be much better off. So I wouldn't worry about the 'long term' damage potential of using cheap oil, unless you are planning to keep the car for a long time or you do a high mileage.

I don't know who makes the 'Tesco's super duper cheapo oil', but it's going to be one of the recognised oil companies (unless it's rebadged cooking oil! ). OK, it won't have such good detergents and additives as the branded stuff, but it can't be that much worse than other mineral oils.

For long journey's keep a pot of oil in the boot. Not sure if your engine has a low oil level warning light, but I wouldn't let it get that low, if possible. You should always aim to keep your oil topped up to the 'max' mark on the dipstick, otherwise the risk of overheating the oil can arise.

[oilman]

Ok, there needs to be some clarification here.

Changing from a 10w-40 to a 5w-40 to a 15w-40 will not cure this problem, they are all sae 40's!

They are all the same viscosities at 100degC and at 40degC they are all thicker than at 100degC. This table illustrates how the viscosities of the various xW-40's converge at 100degC

See here

Viscosity...............at.40degC...................at.100degC.........

0w-40....................75cst...........................14cst

5w-40....................85cst...........................14cst

10w-40...................95cst..........................14cst

15w-40...................105cst........................14cst

The 15w is thicker than the 0w at 40degC but they all thin to the same point.

If the oil is being burnt off (as opposed to a mechanical problem) it would burn off at high temps not low ones as this is where the oil is most vulnerable and the rate should in theory be the same.

Quality is important as a proper synthetic oil is always more thermally stable and therefore less prone to both shear and high temperature loss.

If you feel that a thicker oil will improve the situation and I'm not saying this won't work then a 15w-40 is not the correct choice. You need a 10w-50 or 15w-50, this is 18.5cst at 100degC / 130cst at 40degC and thicker right through the temperature range generally.

I may be wrong but your problem could be caused by excessive fuel dilution which will thin any oil, no matter what viscosity you use but obviously the thicker you start with the better if this is the problem.

Take a look at some of the data on oils here on my website and you can compare the viscosities at various temps for yourself.

http://www.opieoils.co.uk/lubricants.htm

Cheers

Simon

[sotal]

For long journey's keep a pot of oil in the boot. Not sure if your engine has a low oil level warning light, but I wouldn't let it get that low, if possible. You should always aim to keep your oil topped up to the 'max' mark on the dipstick, otherwise the risk of overheating the oil can arise.

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It doesn't have a low level light, I always keep plenty spare with me It seems that the dipstick is biased. The first 1/3 between the mark disappears within a week but doesn't take much to top it up, wheras the next 1/3 takes 4-5 weeks. Not sure how long the last 1/3 to the minimum mark takes as I don't want to let it get that low!

@Simon

Thanks again for the info. I see what you are trying to say... but... do yo

u think there is any credit to the theory which has previously been suggested which is that. When the engine cools down the rings contract and let a little oil seep through which then gets kicked out upon startup. The cat then catched the oil. Hence 5w40 being thinner when cold would seep out quicker??

You suggest that maybe I have excessive Fuel Dilution. Could you expand on this a little. I tried to google it but mainly found info about oil analysis. The bset description I could find was:

Fuel Dilution is the most common cause of oil thinning in diesel engines. Excessive fuel dilution is caused by improper operation, such as extended idling, low compression, and/or defects in the fuel delivery system. The results of fuel dilution are reported as percentage by weight or volume.

I also found the original oil can whilst cleaning the shed out. The first oil used was Castrol RS 0w40 which disappeared from the max mark to the minimum mark within a week and within 500 miles.

I also found the receipt for the oil filter - Mikeb was dead on £7.00 +VAT

[oilman]

No, I don't really go with it because the oil thickens when it cools.

Fuel Dilution.

It's generally is caused by the engine running rich.

There are a few possible causes.

Leaking injectors

Excessive idle time

Incomplete combustion

Cool engine temps

Short trip driving

Chips and mods

Restricted air filter/fuel to air ratio wrong

Worn piston rings - excessive blow-by

Fuel pump over fuelling

Seals/gaskets

Improper injector timing

This is one thing that messes up your oil no matter what oil you use and causes the oil to lose viscosity, increases volatility, accelerates oxidation and causes low oil pressure.

Cheers

Simon

[Cubic Incubi]

Sotal mate

if you think your rings are dodgy you need a compression check.

but a leak down test would be a good idea aswell.

poor oil can burn - normally at high temps you get evaporative loss. sometimes past the rings but often just out of the PCV either way its getting burned in the cylinders as its got no where else to go.

the SAE 10/40 or 5/40 grades motors oils at -18 degrees celcius for the first number and 100 degrees celcius for the second number, it tells us its kinematic viscosity at different temperatures. the kinematic vicosity is not a measure of the force - it is simply the oils ability to flow. it is measured in centistokes.

the meter used to measure the flow is gravity fed, no ther force is applied.

Shearing of oil causes oil to deteriorate, this happens over time when the oil loses its additive properties, this causes friction wear and the oil loses its flow. however oil can also shear if it is the wrong kinematic viscosity at a given temp.

This is why the grade is as imporatnt as the oils structure and quality.

if an oil gets sheared it advances wear, but the oil also breaks down and begins doing less and less lubricating.

cold start cranking needs a good flow.

[sotal]

Sorry this post is breif. I did write a lot but just lost it! :ffs:

Oilman can you help me narrow this list down:

Leaking injectors - I'm guesssing I would see them leaking? There is no leaks in the engine bay. I have had this verified by my mechanic

Excessive idle time - It doesn't appear to

Incomplete combustion - ??

Cool engine temps - It quickly gets to half way. The fan never comes on though unless I sit for a long time in traffic. I was worried that it wasn't working because my fan in my old car used to come on everyday (306dturbo) so on a hot day I just left the engine running after a trip it took atleast 5 minutes. Is that too cool

Short trip driving - I do lots of short trip driving now, most trips are 5-7 miles, but the oil consumption seems worse on long trips (may be psycological - or just due to the fact that one 200 mile drip is equal to 4 weeks of normal trips!)

Chips and mods - I haven't got it

Restricted air filter/fuel to air ratio wrong - Air Filter isn't restricted and is original. NOt sure about the ratio

Worn piston rings - excessive blow-by - Could be, how can I test (catch can??)

Fuel pump over fuelling - Wouldn't have thought so

Seals/gaskets - No External ones are leaking - maybe an internal one

Improper injector timing - Wouldn't havethought so

As I have said before the car runs perfectly, also it recently had it's MOT and passed straight off, with perfect emission results etc. Which of the items from your list would you say actually applied to me and how can I test each of them

[Cubic Incubi]

Sotal, I know what you mean, topics like this can have you going round and round in circles mate.

myself and simon have been trying to point out that an oils isnt measured in thickness it is measured in viscosity which measures its flow. its mass density changes under temperature and affects its dynamic viscosity. its additives affect its shear resistance and its a lot more complicated than just sticking in a 15 grade or a thick grade or a thin grade and just hope, as suggested by mike.

sometimes ignorance is bliss and it makes the head hurt to think about it all. sometimes i wish i just caught the bleeding bus

to check the rings it needs a compression check, you can also do a leak down test and analyse the oil. this would give immediate results.

when I mentioned the oil catch can - this is for 'monitoring' over a period of time whereas the above tests tell you straight away if you have a problem. all these tests can be done at the same time and are relatively cheap.

you mentioned you fan doesnt cut in often, so you either have good temps or the thermostatic fan sensor could be dodgy. and as dicussed the stock gauage is no true indication of actual temps.

If your engine is not the cause of the problem, then the only things left to look at are a good quality oil at the right grade. you've been monitoring your oil consumption and have tried various grades and brands. you wont get consistant oil consumption because of your short journeys and occasional long runs. its well known that shorst journey's can increase oil deterioration and it will have evaporative loss on longer journeys.

as soon as you go for a long drive the oil evaporates, this is perfectly normal on an engine with higher miles, but you can reduce consumption by choosing an oil which best suits the running charecteristics and driving styles.

if you think you may have an engine problem, get it checked and if you do have ring wear - then choose an oil which will best suit the conditions, it will be a temporary solution and you'll have to consider driving styles etc until the problm gets fixed.

realy until you know its not your engine, i cant say its the oil you've tried using which is causing the problem.

do you know what shearing stress is? the net is full of info mate. but dont get yourself worked up with with all the possibilities, just take it one step at a time mate.

[oilman]

If anyone's interested, here it is.

Viscosity Index Improvers.

An oils viscosity will decrease as the engine temperature rises. Viscosity Index Improvers are added to reduce this thinning. They are a key addative in the production of multigrade oils.

VI Improvers are heat sensitive long chain, high molecular weight polymers that increase the relative viscosity of the oil at high temperatures. They work like springs, coiled at low temperatures and uncoiling at high temperatures. This makes the molecules larger (at high temps) which increases internal resistance within the thinning oil. They in effect "fight back" against the viscosity loss in the oil.

"Shearing"

The long chain molecules in VI Improvers are prone to "shearing" with use which reduces their ability to prevent the oil from losing viscosity. This "shearing" occurs when shear stress ruptures the long chain molecules and converts them to shorter, lower weight molecules. The shorter, lower weight molecules offer less resistance to flow and their ability to maintain viscosity is reduced.

This shearing not only reduces the viscosity of the oil but can cause piston ring sticking (due to deposits), increased oil consumption and increased engine wear.

Like basestock quality, VI Improvers also vary in quality. The best quality ones are normally found in synthetic oils (Group IV - PAO / Group V - Esters) and it is important to understand that the less of these in the oil the better the oil will stay in grade.

Which oils require more VI Improvers?

There are two scenarios where large amounts of these polymers are required as a rule.

Firstly in "wide viscosity" multigrades. By this I mean that the difference between the lower "W" number and the higher number is large for example 5w-50 (diff 45) and 10w-60 (diff 50) are what is termed as "wide viscosity" oils.

Narrow viscosity oils like 0w-30 (diff 30) or 5w-40 (diff 35) require far less VI Improvers and therefore are less prone to "shearing".

Secondly, mineral and hydrocracked (petroleum synthetic oils) require more VI Improvers than proper PAO/Ester (Group IV or V) synthetic oils as they are less thermally stable to begin with and this is due to the non-uniform molecules in petroleum oils as opposed to the uniformity of synthetics built in laboratories by chemists.

It is a fact that some synthetics require little or no VI Improvers to work as a multigrade due to their superior thermal stability.

Cheers

Simon

[Cubic Incubi]

Simon, you realy do know your stuff and I'm happy to be having this discussion with everybody, I found the subject of hydraulics very interesting at tech school and haven't paid it any attention for 10 years, its great to learn an oils relationship to the auto engine, its much more interesting than a helicopter transmission, at least for me anyway. But in general second time round i'm enjoying it more as i have an application for it.

If I can add a little more to help describe shearing and oils in general in the high revving/high torque jap motors.

when two metal surfaces are moving between each other a film of oil will coat the surfaces, this needs to stick to both surafaces and must also keep the surfaces apart so they do not rub together - if they rubbed together this would cause friction wear - the oil is in fact a barrier stopping the two surfaces coming together and seizings.

under intense force, and if we use the crankshaft for this example, the piston will be forced down on and the rod will be forced onto the crank, the rod is bolted to an end cap and held around the crankshaft, inbetween the rod, end cap and crankshaft is a bearing.

Oil must flow inbetween each surface but under intense force when the piston comes down, the oil is forced out under pressure from inbetween these surfaces through small oil channels called journals, when the oil is squeezed out a thin barrier remains and the film must be able to remain adhesive as it clings to the metal surfaces, the oil shears when it is has lost its additive properties and becomes 'thicker' its mass density is affected, it has less flow, forms less of a barrier and advances friction wear. All moving parts witness this, low oil also causes this as ther is not enough oil to flow. Generaly the mark on the dip stick defines 1 litre of oil, if you fill it to the top and drive 1000 miles and the level is at the low mark, then it has lost 1 litre of oil over the 1000 miles.

Oil consumption will vary dependant on driving style.

Chemistry had to be applied to mineral oils, old cars at the dawn of the internal combustion age used mineral oils and oil refinery was in its infancy, as advances in oil technology was made and chemistrr was applied, oil lasted longer and did a better job. It had 'additives added' to make it retain its properties longer and to stay clean longer.

As oils becam more and more able to handle higher forces and pressures, engines became more and more advanced, more torque and more rpm. The more 'work' that had to be done to the oil made it cost more, as more went into making it.

(for this example a 40 grade (5/40 10/40 etc);

Mutli grade oils is oil technolgy working at its best, an ability to offer a higher kinematic oil grade when at -18 degrees celcius, but have the same kinematic viscosity at 100 degrees celicius as an oil which was lower kinematic viscosity when at -18 degrees celcius.

This means that all oils at 14 centictockes kinematic viscosity flow the same at 100 degrees celcius but some oils will flow better at -18 degrees celcius because it has a higher kinematic viscosity at that lower temperature.

It is temperature that effect these oils and they are all the same thickness in your engine at 100 degrees celcius when at 'normal' operating temperatures.

I expect to be operating at 125 degrees celcius with my 165 project and may consider a 10/50 in the summer on the track, but 5/40 on the road.

The first part of the SAE multigrade has nothing to do with burning oils it is the kinematic viscosity at -18 degrees celcius and tells its ability to flow. The higher the number the less the oil will flow as the oil has a higher kinematic viscosity, the lower the number the more the oil will flow at -18 degrees celicus as it has lower kinematic viscosity.

In terms of thickness - higher kinematic vicosity is Thicker and flows less

In terms if thinness - lower kinematic viscosity is Thinner and flows more.

Therefore - 5/40 is thin when cold when cold and gets to the parts sooner to build the right barrier needed between the moving parts.

Therefore - 10/40 is thick when cold and flows to the parts slower when cold and taked longer to give the required barrier advancing component wear when cold.

So the thinner or less kinematic viscosity when cold is the best, and they all get up to the same 'normal' opering temperature kinematic vicosity or thicknesses.

This has nothing to do with burning oil.

Using the wrong oil when cold cranking advances oil deterioration, albeit slightly. More so if the oil is under to much shear stress or engine force before it is allowed to build the correct barrier. Even just idling. As soon as you place force on those crankshaft bearings, you want a barrier & a nice film of very adhesive oil.

Therefore a good fully synthetic oil of a 5/40 grade is going to be good for an engine which needs this kind of protection when cold, such as one with wuick response and high torque, this means high force and shear stress and high rpm when cold. And it will give the same protection as a 10/40 semi synth when at operating temperature.

Because as mentioned, it takes additives make mineral oils be able to withstand such temperatures and shearing stress or forces or torque for that matter, it is chemistry which has allowed higher performance engines.

The highest performing engines all use fully synths because of oils ability to last and protect, it is chemically engineered more so than a mineral oil with some chemical additives.

A proper fully synthetic uses the finest chemical engineering, and why bother developing a replacement for a natural drilled resource without making it better. It lasts longer. When oil shears it gets too thin, it is squeezed out under force from in between components, the barrier is broken and the engines advances friction wear and can seize. Semi synths - even the very best, do not last good as fully synths. The additives cant last forever.

This is what happens to a poor oil, and a poor oil can be semi synth or fully synth, not all fully synths are fully synths though most of them are better than poor semi synths.

And to finish, and this bit i ask to be clarified on - oil vapourises in the crank case and coats everything, the more esters, the more the oil coats everything. the better the detergents the more the blow by is cleaned frrm the oil and it seperates in the oil vapour. The more vapour the less esters and the more dirty vapour the greater the blow by gases are mixed with the oil and the oil gets dirtier.

The positive crankcase pressure would otherwise force the blow by gases out of the PCV vent to be recirculated. Poor oil which thins out too quickly will increase dirty blow by and will burn oil and gum up the intake manifold, injectors etc. This can cause combustion problems and can lead to ring or valve wear and general combustion poblems.

good quaily oil which is engineered to do its job at all temperatures, it must have excellent adhesive properties, it must good at providing a barrier at the normal operating temperatures, it must stay clean longer and must have low evaporative loss.

You want the blow by gases to blow out, not the oil. you want to keep the oil and blow by gases seperate.

Blow by is a natural function of the engine under high forces and rpm when the engine is hot and the cylinders have expanded and a little leaks past the rings, a good oil must do its job at these high temperatures, as well as flow well when cold.

Again, If you think the engine is the problem - oil analysis will tell you what your oil is doing. A full leak down test and compression check will tell you everything else. The rest is starting with a good oil at the right grade and then monitor comsumption. Consumption must be monitored, and even the best oil will get dirty and have evaporative loss and need changing - just pouring in a litre every thousand miles ends up leaving the oil rather dirty. Poor oil condition needs a nice drain down and flush through with clean oil every now and agin, and a new filter. Excessive blow by engines need more frequent oil changes. Simply constantly topping up means you are just diluting dirty oil constantly and it will start to just evaporate at an alarming rate. We have discussed the causes of ring wear. Wrong oil, poor fueling etc.

If you think there is high carbon deposits in the intake manifold and the injectors and the valves etc then you can remove and clean the throttle body and you can put injection cleaner in with the fuel. the minimum amount should be tried first and the engine monitored.

Fuel additives which clean the entire fuel system wont be able to clean excessive evaporative loss caused by high shearing and dirty oils or poor oils and this can cause the problems explained.

Therefore poor oil, good oil of the wrong grade or especially poor oil with the wrong grade for your engine can cause high evaporative loss, carbonised deposits in the fuel and combustion components, can cause ring and valve wear, can advance friction wear and can cause component failure and seizing at high rpm.

Modifications will advance this as will aggressive driving style. Modifcations affect the normal operating temperatures and the forces applied and shearing stress, so oil longevity and ability to protect must be considered.

Poor Oil choice is the cause of most cases of engine failure and high oil consumption.

Often this stems from not understanding the nature and the complexity of oils under force and high or low temperature.

Thick or thin isnt the correct term to describe oil. It is all flow and it is all viscosity. Its mass denity changes with temperature, it feels thinner when it is hot by touch, its suprising to learn that some are thinner when cold, whilst being the same viscosity when hot. And it is this that confuses people . IMHO I would use a SAE 15/XX in Death Valley, Nevada, not in the uk, it is too thick. I would use SAE 0/XX in the minua temps of Russia.

[sotal]

ouch my head hurts from all that! :bookworm:

Thanks Carlos for making it a little easier to understand. I read Simons post twice and gave up in the end. I can see the words and understand what they mean, but when it was all put together I had no idea!

Ok I now have no idea which oil to put in, and it this rate I may well stick to what I know and put 10w40 in again.

I just had a quick scan over the posts and noticed that carlos suggested 30 oil somewhere (5w30 or 10w30 can't find it now from the post window!). Was this a typo or did you mean to actually lower that number as well?

Carlos you mention a leak down test and compression test. I have completed a compression test and all 4 gave very close readings all perfectly within the specifications. Obviously I have no history of compression tests so cannot say that they haven't changed over the life of the vehicle but I can say that they all look good.

I have had a quick read about Leak Down Testing and there is even an article on how to make your own leak down tester. Is this something I would be better going to a garage for? How long would it take to test my car?

I would like to know where the oil is going, even if the answer tells me I might as well leave it! Atleast then I would know what or where it is!

[Cubic Incubi]

Right

Marathon post - compare oil prices, look at grades, oil industry insider info and lots of other stuff thrwon in, everything you need to know about oil is in this whole thread I reckon. :P

First for sotal, leak down tests, I would find a good approved garage which does this service, reccomended in your area. I personaly wouldn't try my own leak down tests, compression tests yeah ok, but not leak down, of course depends on your ability but its pretty specialist imho...

here's 7afe compression data on this online manual http://www.celicatech.com/imagearchive/bgb...cifications.pdf again thanks to celicatech for hosting this article (you may need to register at the site to be able to read the online pages)

Right, for the first time in a fortnight apart from seeing the quack, yesterday I went out, to the wholesalers with the wife to get some meat for my hounds, whilst I was there I decided to look at all the oils they had, compare prices and look at the specs.

I wrote it all down, and will post all my findings. I also read an article from the chief chemist at Silkolene which Oil man was good enough to send me, which I have read and was very interesting. I'll talk about that later, but it basically confirmed what i speculated in the last post about buring off oil through the inlet manifold.

But first, in addition, I spoke with my Dad (an this aint a my Dad said this thread - its unbiast professional advice) who I managed to contact regarding his step dad passing away few days ago, He managed to jump on the helicopter and got off this huge pumping rig off the coast of norway.

I spent the afternoon with him yesterday and his brother, also a marine angineer, popped down to take off my down pipe for me, take it away and weld it for me, as i'm a tad disbled at the mo.

So all in all, the three of us had a good natter, as ever the conversation as it always does turned to engineering, and high altitude sky diving B)

My Father has been a marine engineer for over 30 years, he is now a first class, got all his tickets and qualifications, enough to put any man to sleep - so in other words, he knows his stuff. He gets head hunted now and paid wads of cash - lucky bugger.

He's an oil man in the true nature of the word, in the sense that for over 30 years he's ran huge super tankers up the Suez Canal and anywhere else he can haul the stuff to make a buck, in the 70's getting fired at by muslim rebels, aswell as delivering tanks to the middle east etc, he's worked off shore in mexico, japan, well - everywhere. been all the way around the world a dozen times and back again, at least 100 times or more - carrying oil, bananas, you name it - he's hauled it. And along the way has maintained some of the most complex hi tech and some of the most antequated piles of metal this side of Venus.

Constant hum and smell of oil, all day long. pure heaven

anyway, lets not meandre off topic, i digress....

So he's been carrying oil, pumping oil, drilling for oil, worked on diving vessels, supply boats - you name it, he's seen it - refinery's etc etc.

So, this is what he tells me about oil - we dont need to go into the refining process, you can look that up for yourself on google.

Now then, oil is in the ground, you drill it, inpsect the quality and it its any good, you pump it out.

Not all oil is good enough for certain uses, but not much of it gets left in the ground.

Oil from different oil fields has different properties, so the refining process is different for different oils.

Theres an oil refinery in Cassington in London, there's oil refineries all over the world, france, red sea, middle east etc etc. All the oil gets pumped, hauled, tankered to these places and it all gets refined.

Individual companies rarely drill, pump, haul, refine and can there own brands, but of course some do. but they tend to flog all the oil off to ther smaller firms who distribute it. its the age of the sub contractor.

There are only a handful of firms who do this, all the rest of the oil gets hauled from the refineries and gets canned particular to the grade and gets a sticker slapped on the can. its all the same from that particular refinery, dependant on grade alone.

Some firms 'may' take the oil away and do stuff to it, then get it canned and stick their own name on the can - that is the expensive stuff, becusae its had more done to it after first stage refining - how do you identify it though? the blokes in Halfords wont have a clue what kinematic viscosity means, never mind who canned the oil in the first place.. this is our problem.

We - the man on the street have no idea where the oil is from. cheap oil can be sold in expensive fancy bottles with big labels and we wouldnt have a clue, it could be the exact same oil, never seen any changes to it since the first refinery process, buts its got a big fancy sticker and can be the same as the supermarket brand thats a fiver less - its all gambling with your engine until you stop - take stock and do some rearch for yourself.

And you can be assured that these oil firms dont buy them in little 5 litre bottles and stick a label on them, they buy them by the tankerload, so where does the oil come from?

It comes from wherever it is cheapest, these firms are just like any other business, they are in business to compete and make money - billion dollar profit, its a race to pump it all out of the ground. Oil markets dominate the worlds economy.

we have no guarantee the oil we used 18 moths ago is the same oil we used today, even if its the same brand and same grade, it could have come from a different oil field, a different oil well. Unless you write to the oil company and ask the right questions, how do you know?

Like already mentioned, the oil has to be given additives to make it any good, old fashioned oils are for old fashioned rough engines, as oil became better refined and able to cope with higher tolerances, engines developed.

Question, is your engine old and antiquated? just because it has high mileage on it doesn't mean it needs old fashioned oil does it?

As far as i'm concerned, if you think you have component wear and failure, old fashioned mineral oils will do more damage, they wont make it last longer, they will advance wear. So will thicker cold cranking oils, if anything you want a thinner cold cranking grade with more flow, not less and i cant work out this 15/40 summer consideration.

Now, I'm not suggesting that everybody has to use the same oil and it must be what F1 racing teams use, far from it, all i'm saying is that a 'good' quality oil at the right grade is what keeps the engiine performing.

Poor oil is in my experience and opinion the single biggest factor in advancing friction wear, component failure and ruining engines, it is only recently because of getting rid of the waste that goverments are starting to demand that cars last longer and they must be recylcled.

Now, my old man told me that he has seen oils of the same grade, from different oil fields and different refineries and they are different collors, smell differently and definatley have different 'pour' qualities at whatever embient temps he was in at the time.

the pour is just the same as flow realy, the oils resistance to moving around. its normally used to test cold cranking grades.

Now poor oil has to have more additives, so more additives isnt necessarily a sign of a good mineral oil, it can mean a poor oil, or it can mean a good oil with good additives, and again, this is our problem.

We have absolutely no idea where the oil is from and if it is of good quality. its all a gamble.

Unless you have the batch and serial numbers and can contact the name on the label, and have a degree in the refining process and are aware of the different oil fields across the globe and the quality of the oils - how on earth do we find out the quality of the oils?

The more we learn the more of a big sh*te sandwhich this is becoming and the bigger the bite we all have to take :(

Now, looking at the whole picture, which oils do we buy?

We buy the most advanced.

Believe me, the engines in all of our celica's are advanced, very advanced, the Japenese have made some damn good stuff in the last 30 years, lets compare the revision 1 3SGE engine in my 1987 celica, compare it to the Carb fed lump in my 1987 Frod Capri which went to the scrappers 6 years ago - which one was more refined? The jap plastic missile of course, as always.

Oil advancement at the time of making that engine was way way behind.

A 80K Generation 6 engine is in my opinion not even half way through its life yet.

Using the right oil will make it last for a long time, they are built to withstand some punishment. The only thing which will make it last as long as an older engine, is using older style engine oils. good Oils make engines last long combined with good engine advancements. Japanese engines can see 300K if looked after well.

I've chatted with guys in the united states who are clocking over 200K miles in there FE Gen 5's and gen 4's, these guys look after their oils.

The most advanced oils around today are Fully Synthetics, proper fully synthetics, not hydro cracked minerals, and they are expensive, because they do the job properly, protect longer, work better, and at the end of the day costs are the same, becuase you dont have the issues that you have with a poor mineral based oils burning off under stop start short journey town like driving.

A very good and expensive semi synth could be a mineral oil of such a poor quality that it has that many other stuff thrown into it, its being kept together by the very things that keeps a fully synth together. who knows?

Again we have no idea what oil we are buying when it says semi synth, its all guess work, but unless you get the oil analysed after its been running in the engine, you dont know what its realy doing, how long its protecting etc.

OK, now i'm going to list the oils for comparison that were for sale at the wholesale place - this in no way a reflection of everything available on the market - just remember that cheap oil is often just that, old fashioned oil for old fashioned results.

If you have engine wear, I just dont rate these 15/40 semi synths for high mileage engines, where is the proof? its just old oil technology as far as i'm concerned with a higher cold cranking grade? it just doesnt make any sense at all.

A worn engine needs the best advancements in protection to stop it wearing more as far as i'm concerned.

If you have engine wear, get it fixed or replaced, I once thought that I could 'save' the engine with these fandangled oils that claim to protect engine wear? how the hell can they claim that? if its worn its knackered at the end of the day.

Right - oils

These are the prices at Costco - a nationwide american backed wholesaler, they sell everything, just like Makro, these are the oils and prices found in the Geateshead store;

All prices include VAT and remeber these are wholesale prices, so add on what you would expect to pay elsewhere on the high street..

Castrol GTX

High Mileage for engines over 75K?

5 litres

£7.95

SAE ? didnt say but i reckon its 15/40 - who cares its for high mileage and its cheap? just sling it in ueah, right

API SL

ACEA A2/B2

Mobil

Super S

4 litres

£12.44

SAE 10/40 Semi Synth

API SL/CF

ACEA A3/B3

reccomended VW 505.00 - MB (merc benz, daimler chrysler) 229.1

Mobil

Mobil 1

4 ltres

£23.47

SAE 0/40 Fully Synth

API SL/CF

ACEA A3/B3/B4

recomended VW 502.00/505.00 (1/97)/503.01/ - MB 229.3/229.5 -

Opel GM LL-A-025/LL-B-025 - BMW long life - Porsche - Saab.

Chevron (Texaco, London) (made in EU?)

High Mileage

25 litres

£17.61 :o

SAE 15/40 multigrade

API SJ/CF

ACEA A2/B2

CCMC G4/PD2

reccomended VW 501.01/505.00 - MB 229.1

Now onto what I use.... and agin it's not gospel and the best oil in the universe, its just the oil i'm giving a go given what i've learned, if its no good i'll ring oil man and get him to deliver to my door.

Chevron (Texaco, London) (made in EU?)

Supreme Performance (Race Proven - apparently although which race i dont know)

4 Litre

£11.98

SAE 5W/40 Fully Synthetic

API SL/CF

ACEA A3/B3

recomended VW 502.00/505.00 - MB 229.1, BMWlonglife-98 - Porsche

"A 100% synthetic multigrade" - all cars, even turbo and super charged - but especialy high performance -well thats all jap celica's then.

"Exceptional low temp pumpability, for maximum engine life"

"ultimate protection against wear (erosion) and corrosion in extreme temps for maximum engine life"

"compatible with all high quality oils"

"Warning - contains Calcium long chain alkaryl sulphonate"

Now then, consider i'm buying this wholesale and they buy it in massive bulk, and its a USA backed firm...- so its cheaper than it would be allready if it was in Halfords by i reckon 50%, consider the same brand does 25 litres of 15/40 semi synth For £17.61. for the same amount the fully synth would cost £ 74.88.

So thats a massive price difference aint it, massive price difference, even at massive bulk discount at a wholsalers.

Your paying the extra money for the latest advancements in oil technology. thats why its expensive, and it doesnt have fancy pants advertising either - its all word of mouth.

look up api and acea grades on the net.. knowing what an oil label means is important.

Soon, the oil fields will stop pumping and you won't have a a choice, oil will bhe in short supply and synthetic fuels and oils will replace the pumped fossils...

A modern japanese engine is not high mileage at 75K, thats nothing to a good solid jap metal lump. jap high revving engines wont last as long as a low down torque FE engine either, the very nature of the GE engines mean they just wont last as long, they have higher forces put on them - so the FE engines are like a diesel engine in a way that they have low down torque and have power from the word go. Why start putting cheap backwards technology into the engine when its a modern engine and deserves the best in advancements in oil technologys. It just doesnt make sense - oil technology is really just now beginning to catch up, its only been in the last 10 years that these excellent quality fully synths have finally been developed. If I had a crude old car with high mileage, I would use old crude 15/40 semi or even a straight 40 , but our engines are far from crude, the are among the best engineered twin cams in the whole world, so they deserve the best oils.

Yes, I did reccomend a 5/30 fully synth all year round protection for the 7AFE, and reccomended 5/40 fully synth during the hot summer months when you can expect higher engine temperatures. because you are doing short journeys Sotal, you want maximum protection.

Now one last thing, if for example and this is mere speculation, your dip stick has a problem (i'm sure ive heard that some gen 7's have a dip stick maufacturer error)

imagine your dipstick is giving you a wrong reading, imagine all this time you've been slinging in 'too much' oil :o the oil will be picked up and slung against the pistons, will be pumped into the cylinders, the oil will be sheared no doubt, it will lose hydromdynamic properties. generaly it will be sludges up and pumped out of the PCV vent... before you go checking the dipstick though and taking off the sump, ask some other ST owners what they find... some i ask dont even know whats in it, its just what the local garage put in, whatever that may be?

also, constantly adding a litre of oil to poor oil which has burned off is just diluting a horrible mixture in the bottom of the crankcase, this is just going to burn away quicker and leave you with the same problems. right through the PCV into your combustion cylinders, gumming up valvestem seals and rings and injectors etc etc.

I know that fully sunth is more expensive, but i can afford £11.98 for 4 litres all day long. its not being bought from a fancy shop with a fancy sticker and can and isnt advertised everywhere in magazines and on the TV. its just a good proper fully synthetic. I will let you know how i get on with it. i'm almost certain its from the French refinery - or it could be the Red Sea refinery, is that EU?

you've got to take everything into consideration and do what you think is the best thing for you.

a 15/40 and a 4/40 is the same thickness, or there abouts at full operating temps, and it is this that burns oil. poor quality oils burn away quicker - wether they be fully synth or semi synth. finding a good oil is trial and error and can be just good luck.

like my dad confirmed, two grades of 40 multigrades side by side can be very different and offer different protection at operating temps, anybody can bottle an oil, stock something in it, stick on a label and say it does this and that. its all hype, i never believe hype.

Oil man is heavily respected throughout the motoring clubs, SIDC - GT4OC etc and sells a lot of oils at jap shows and events, brings it all in a van and you take it home on the day, or he delivers to your door - the oils he sells are race proven.

I'm going to give this oil that I've found a bash first and if its no good, i'll give him a call and get Silkolene Pro S 5/40 Fully synth for ultimate protection under the heavy forces i intend to put on the oils and becuase i expect to get a few BHP out of choosing a good oil.

15/40 from cold cranking is making the engine labour to get warmed up and i'll argue that with anybody all day and everyday. i just can work out why its clssed as a high mileage oil, nothing about 15/40 grade makes sense from a worn engine point of view, if anything it'll make it worse, its gum everything up one evaoration after loadsa bashing at cold cranking..

and a 5/40 definaltely can not seep when cold, thats daft as it very very thick, even at 35 dgrees in the height of summer.

Simon and I arent oil heroes or modifying gods - we just look at the facts, i've said the same thing as simon, except he's in the industry and i'm just and enthusiast,and still learning and getting stuff accurate and precise - but I aint going to spend up to £10K on a car and stick oil technology from 15 years ago into it - even if the engine was built 15 years ago - I want the best protection possible.

A good semi synth will do the job, but good fully synth will do it better.

If you burning oil, you need to look at the engine, talk to other owners worldwide with the same engines, and find out how wide this issue is. Like I say, guys in the usa change there oil more regularly and see over 200K from FE celica engines, thats high mileage on a FE.

If the oil is burning away, change it, dont just keep adding to it - remember its not the amount of miles or number of days that tell you when you need to change the oil, its the 'driving stlye' lots of use and the car will drink less, if its lots of short journeys and then a big run out, your gonna see hefty oil consumption as the oil has wron on those short journeys and wont give maximum protection at high temps and it just breaks down and burns away.

I asked if my Dad thought a fully synth was better, he said you bet, its going to ruin my trade evnetualy, but he reckons he'll be long gone by then.

As engines become more advanced, fully synths will be the only way to protect them, oil will still be pumped for hydraulic use and transmissions and for making all sorts of stuff from plastic bags to office chairs.

Even all diesel engines as they become more advanced will need fully synths.

But again, a good modern semi synth will give you protection, but with 15 year old technology - a good fully synth is technology now, and in terms of technology its the diference between the Bi-plane and the Space Shuttle.

by all means keep on using it but in terms of best, you decide for yourself.

gummed up valves and pistons can be cleaned with fuel additives, and as discussed if your burning oil it has to go somehwere - straight out of the top of the head via the PCV vent and back to your inlet manifold gumming everything along the way

thats the kind of problems my old man had with old oil technology in his MK2 cortina back in the seventies, it cant be good for a modern jap engine ;) those old engines didnt last more than 100K on those old oils ..

ok, another marathon post over, i reckon if anything ive definately satisfied my own curiosity about oils, having had the last fortnight on my back has been great to do a bit of research. :bookworm:

thanks to all who took part, i've really enjoyed it :D cheers

regards

Karl

[sotal]

wow That was a good post. I'd finished my dinner half way through as well.

Infact I've spent so long reading I haven't got time to post a reply! I'll try and digest everything you've said and get back with a reply - but I've got a busy day or two

*edit*

One quick question though....

Can you get a bad fully synth?? Ie is it worth buying the cheapest fully synth??

[cookci]

i run mine on 5W/30 all seasons. The BHP gain is nice over running 5W/40. On the rare very hot days of the year though i just dont thrash it.

The only reason i can think of running 15W/40 over 5W/40 is if you have a leaking sump! If so i guess u should get it fixed rather than being lazy :D.

Sotal ive run "cheap" 5w/40 F/S from my local trade desk and have no complaints. infact it seemed to last longer than the Halfords stuff. Cost me £13 for 5 litres. I can get u the brand of it if you like?

does anyone know where i can get F/S 5W30? Ive only ever seen P/S?

[Cubic Incubi]

yes, any poor oil will be worse than a good oil.

a good semi synth will be better than a naff fully synth - its just about how good the oil is.

(this is going to sound so sad and anorak like) but i've got two cans of oil right in front of me, both fully synth, one is the chevron as described above, the other is as follows;

Motorway (Comma oils, Gravesend)

5L

£14.99

SAE 5w40 fully synthetic

API SJ/CS

ACEA A2/B2

and that's it, no claims, no stickers. I bought it to use as a flush oil when i put the 3sge replacement engine in the rag top, just used it to flush the engine, then put fully synth in it.

I definately wouldn't run it in the engine properly because its a cheap fully synth and is most probably hydro cracked stull, it was over priced as it is and i bought it from one of those motorist bargain shops on the high street who put sticky price labels on everything where everything is overpriced anyway but it's convenience.

so yes, fully synths can be cheap - the stuff I buy can be sold again, as a trader for profit. so i guess it gets sold for about £25 ish in the shops.

I buy loads stuff from Costco, just saves me a few bob is all.

[Cubic Incubi]

The only reason i can think of running 15W/40 over 5W/40 is if you have a leaking sump! If so i guess u should get it fixed rather than being lazy :D.

←

well they are both as thick when running at normal temps, and when its about 30 degrees out side its still gonna be very very thick.

still not thin enough to seep realy, defo not past the rings.

any oil seeps should be sorted, it just a bit of that silicone type seal stuff and tighten the bolts up.

£13 is a good price for fully synth from a trade desk, like i say I pay £12 from trade to be sold again, not that i b uy it to sell, havent got the time or the will, the stuff i got though from the local motorist shop proably cost him about £6 if that - he's a right robber just as a flush was pretty poor i reckon, you can actualy look at websites for most oil manufacturers and find out who they get the oil off. even then you have to guess where its from, if its a semi, and if its real if its fully.

[sotal]

OK - just got 15 mins,

As everyone has gone to so much trouble (Espicially Carlos!) I will try whichever oil they suggest (within reason sub £15 would be nice <_< )

I will then test it in the car. I will do a full oil change along with a new Toyota Filter. I will record it's level and the types of journey I do and we can see how well it lasts.

So go ahead - I'll give the choice to Carlos as he has put so much effort in. Choose me a brand of oil and a specific weight/viscosity and I'll try it (If possible can you give me a couple of brands as my local motorfactors may not have your first choice)

I think that it will be a good test - If we then find that it disappears quickly we can try an alternative and come up with a theory as to why one would be better than another. I think it is the best solution to stop this thread going round in circles!

P.S. Just to clarify I'm not trying to be lazy and get others to choose my oil for me, I just figured this was the best way.

Also - Carlos I can't imagine what your bedroom looks like if you are bedridden and have two cans of oil in front of you

[cookci]

i used...

DX THREE SAE 5W/40 FULLY SYNTHETIC...

API SJ/SH

API CF

ACEA A3-96, B3-96

VW 500.00, 502.00, 505.00

MB 229.1

:D

[Cubic Incubi]

yeah, ive kinda sussed all the good fully synths have reccomended manufacturers on them and the A3/B3 acea categories... and there all SL/CF

(the bottle of cheap comma full synth is A2/B2 & has SJ/CF *but* has a sticker on the neck of the bottle, read "new improved formulae, api SL") yeah right becuase the little sticker stuck on the neck, after the main label was printed and stuck on says so...

well there's all the main brands, then there's the racing type brands, just have a look on the high street and try it. I've also founf standard (black bottle) STP injector/fuel system cleaner to do the trick aswell... dont know what you've tried..

P.S all advanced motorcyles are using fully synths and have been for a while...

does you oil need changing? may aswell squeeze a few more miles out of it if its not ready for a change

i'm feel up on the sofa, so no worries of oil in bed with me.... lol...

cheers

look through the yellow pages for motor part factors, who sell blue print stuff etc, you'll find they will sell you stuff at trade prices, I get trade prices at a couple because i'm akways in and out for stuff and they get to know you, bearings, cv boots, that sort of bits and bobs..

oh, by the way, we managed to get this thread to page 2, not bad eh!!

[Cubic Incubi]

according to celica club, all st's drink oil like a fish after about 60K, most sem to use gtx high mileage, handbook says 1000K = 1 litre.

but i still dont buy the 15/40 semi argument though, all it is is harder cold cranking.

if you want a thicker oil then you want a 50really in summer and a 40 in winter - thicken the working temps, not the cold crank temps.

ive started a thread on TOC! now aswell to get their opinions

[sotal]

It does seem to be more of a problem than I thought - I just had a read through TOC!. I posted there about a year ago but didn't get much help!

I do like the thread on there about the ST being faster in normal conditions than the GT! The GT seems to only be faster in drag type situations or once you get past 100mph!!

[oilman]

Of course there are things as bad synthetics, there are many that are not synthetic at all, they're petroleum based and not synthetic at all.

Read this and you'll understand

A word of caution – You get what you pay for!

Below is an article written by John Rowland, Silkolene/Fuchs Chief R & D Chemist for 40 years.

Quote:

Costs of synthetics vary considerably. The most expensive are the “Ester” types originally only used in jet engines. These cost 6 to 10 times more than high quality mineral oils.

The cheapest synthetics are not really synthetic at all, from a chemists point of view. These are in fact specially refined light viscosity mineral oils known as “hydrocracked”. These have some advantages over equivalent mineral oils, particularly in lower viscosity motor oils such as 5w-30 or other oils with a low “W” rating such as 5w-50 etc and they cost about 1.5 times more than good quality mineral fractions.

We use several different grades of this base oil, where appropriate. This is the “synthetic” which is always used in cheap oils that are labelled “synthetic”. Yes it’s a cruel world, you get what you pay for!

Now, you may ask, why are these special mineral oils called “synthetic”?

Well, it was all sorted in a legal battle that took place in the USA about ten years ago. Sound reasons (including evidence from a Nobel Prize winning chemist) were disregarded and the final ruling was that certain mineral bases that had undergone extra chemical treatments could be called “synthetic”.

Needless to say, the marketing executives wet their knickers with pure delight! They realised that this meant, and still does, that the critical buzz-word “synthetic” could be printed on a can of cheap oil provided that the contents included a few percent of “hydrocracked” mineral oil, at a cost of quite literally a few pence.

So, the chemistry of “synthetics” is complex and so is the politics!

The economics are very simple. If you like the look of a smart well-marketed can with “synthetic” printed on it, fair enough, it will not cost you a lot; and now you know why this is the case.

But, if you drive a high performance car, and you intend to keep it for several years, and maybe do the odd “track day”, then you need a genuine Ester/PAO (Poly Alpha Olefin) synthetic oil.

This oil costs more money to buy, because it costs us a lot of money to make, very simply, you always get what you pay for!

Unquote:

There are no free lunches guys - sorry!

Cheers

Simon

[Cubic Incubi]

So on the whole, would you choose a hydrocracked mineral/petroleum based Fully Synthetic over a Good semi Synth, or is the hydro cracked stuff just a no in any event?

Because we need to know that the fully synth we are buying is in fact a fully synth!

?

[oilman]

I would always choose any fully synthetic over semi-synthetic for quality but what is it made of is the key.

Finding out, well...............that's another story!

The best quality available in the Uk is the likes of Mobil 1, Silkolene PRO, Motul 300V and 8100, Fuchs Titan Supersyn and most 0w-30, 0w-40 oils as these require decent basestocks to formulate.

Most oil companies will not expand upon the statement, "it's fully synthetic" so the only way to tell for sure is by analysing the technical date carefully!

Here is some guidence that may come in handy or just ask me to sell you a "proper" fully synthetic ;)

There some important numbers to bear in mind when looking at technical data sheets and you should be able to obtain these either by looking at the sheets or asking the oil company for the figures.

COMPARING TECHNICAL SPECIFICATIONS (If you can get hold of them!)

When comparing several oils for use in your vehicle, the most important thing to do is to compare the technical specifications of the same viscosity oils.

This is the only way to objectively determine which oil has the best protection and performance characteristics.

There are some useful specifications you might see on the technical data sheet for any given oil viscosity although many manufacturers do not publish the full story which just confuses the matter as you need to compare the same figures to make a true assessment so you may need to ask!

Kinematic Viscosity @ 100 degrees C

Kinematic Viscosity @ 40 degrees C

Viscosity Index (VI)

Pour Point

Flash Point

High Temperature/High Sheer Viscosity

Comparisons can be difficult without the full picture, but not impossible. Here are some of the specifications which are the most important when looking for the best performing oil.

WHAT DOES EACH SPECIFICATION MEAN?

The most commonly found specs are kinematic viscosity at 100 degrees and 40 degrees C, VI (viscosity index), pour point, flash point, and the HTHS number (high temperature/high shear).

Kinematic Viscosity @ 40 degrees C

Although this test is not used specifically for classification of the oil as a certain viscosity, it is used for establishing the Viscosity Index of the oil. If the VI Index is listed then you can safely ignore this specification, even though it's on all tech sheets.

Kinematic Viscosity @ 100 degrees C

Once again this test is really only useful for establishing the viscosity classification of the oil and for determining it's Viscosity Index. If the VI Index is listed then you can safely ignore this specification, even though it's on all tech sheets.

Viscosity Index

An oil's VI rating refers to its ability to maintain a consistent viscosity over a wide temperature range. The higher the VI, the better this ability. I wouldn't purchase an multi-viscosity oil that has a viscosity index below 140. The VI of a good monograde oil should be at least above 100. One thing to keep in mind regarding VI numbers is that they only refer to an oil's ability to maintain consistent viscosity when new. They tell you nothing about how quickly the oil will lose this ability to maintain its viscosity over time.

The fact is, even if an oil has a VI of 180, it may only hold that VI rating for a couple thousand miles and this is extremely important! This is where the HTHS number is very important.

A rule of thumb is that Petroleum oils are much more likely to have declining viscosity indexes than synthetic oils. This is because synthetics require a far lower percentage of VI improvers to boost their VI numbers. VI improvers can break down very quickly. Hence, the less VI improver needed, the less likely an oil's VI will be affected over time.

Most tech sheets list the viscosity index.

Pour Point

The pour point of an oil is a temperature -15 degrees C above the temperature at which an oil shows no movement when its container is inclined for 5 seconds. In simple terms, the pour point is the lowest temperature at which an oil will actually flow. This does not mean that it would easily pump through an engine at this temperature - just that the oil still acts somewhat like a liquid at this temperature.

Keep in mind that in oils where pour point depressants are necessary (generally, petroleum oils), the pour point of the oil will rise slightly every time your oil sees cold temperature weather. This is because those pour point depressant additives are being used up. Synthetic oils do not use pour point depressants, so they will hold a consistent pour point for a much longer period of time.

This spec should be found on every tech sheet. Of course, if the oil is not designed for low temperature operation, this spec is obviously less important. But, if you're looking at the spec sheet for an oil that will see cold temperature operation, the pour point should be on there.

Flash Point

The flash point of an oil is the temperature at which the oil vaporizes enough for the gas to become momentarily flammable in the presence of a small flame. There are other conditions and requirements for this test, but in general it is that an oil reaches its flash point when it begins to significantly vaporize.

In today's modern engines a flash point under 180 degrees C is unacceptable. Look for an oil with a flash point of 200 degrees C if you want the good stuff. A good quality synthetic will be higher than this. If this specification is not available, find another oil.

High-Temperature/High-Shear

This test is a simulation of the shearing effects that would occur within an engine. In fact, it's actually designed to simulate motor oil viscosity in operating crankshaft bearings.

Under high stress conditions where shearing can occur, the VI Improvers (polymers) break down. As they do, the viscosity of the oil decreases. This is what the High Temperature/High Shear test checks for.

The HT/HS test is measured in Centipoise (cP) as the Cold Crank Simulator test is. However, in this case, because you're hoping for the least loss of viscosity with an increase in heat and stress, you want the cP value to remain high.

Each SAE multi-viscosity grade has a specific lower limit for the HT/HS cP value. If a multi-viscosity oil cannot achieve a cP value above that limit, it cannot be classified under that viscosity grade. For instance, according to the SAE specifications, an oil must achieve an HT/HS cP value of 3.7 or higher in order to be classified at the 15w40 viscosity grade. The thinner the oil the lower the number.

So, whether this data appears on a manufacturer's tech spec sheets or not, the company always has the data and it should be available on request.

MEETS OR EXCEEDS ALL REQUIREMENTS

Other companies might list a test specification (standard or non-standard) and then put something like "Meets or Exceeds All Requirements". This can be a cop out unless the oil in question is a specialist "race" oil which is tested on the track (Motul 300V is one of these specialist "race" oils).

Any oil on the market should meet or exceed any standardized requirements, otherwise, it shouldn't be on the market.

A good tip is to look for oils manufactured by companies that are not afraid to publish the results of testing for comparison to other oils.

Be aware that some companies will utilize non-standardized testing procedures so they can provide information which looks impressive but can't be compared to other oils in the industry which is generally unacceptable.

If you want to benchmark oils then here are a few "top" oils that you will find hard to beat and I quote these as a standard to aim at eventhough it's a very high standard to set.

Silkolene PRO S 5w-40

KV 100DegC 14.89

KV 40DDegC 92.35

VI Index 169

Pour -51 DegC

Flash 210 DegC

HTHS 4.07

Motul 300V 5w-40

KV 100DegC 13.80

KV 40DDegC 80.80

VI Index 176

Pour -36 DegC

Flash 216 DegC

HTHS 4.51

Silkolene PRO S 10w-50

KV 100DegC 18.17

KV 40DDegC 116.49

VI Index 174

Pour -33 DegC

Flash 210 DegC

HTHS 5.11

Motul 300V 10w-40

KV 100DegC 14

KV 40DDegC 89.5

VI Index 161

Pour -36 DegC

Flash 226 DegC

HTHS 4.19

Silkolene PRO R 15w-50

KV 100DegC 18.2

KV 40DDegC 130

VI Index 156

Pour -35 DegC

Flash 200 DegC

HTHS 5.23

Motul 300V 15w-50

KV 100DegC 17.8

KV 40DDegC 128.1

VI Index 154

Pour -36 DegC

Flash 215 DegC

HTHS 5.33

Mobil 1 Motorsport 15w-50

KV 100DegC 17.4

KV 40DDegC 125

VI Index 153

Pour -45 DegC

Flash 230 DegC

HTHS 5.11

Hope this helps.

Cheers

Simon

[Cubic Incubi]

That's more to the point, we find there is always more to consider, and it goes towards us researching the choices.

We do have a choice with oils, and we 'can' go with the 'flow' (no puns intended) :D

Thanks Oilman for another good post.

cheers

[sotal]

Well I popped into Toyota on my way past to see if anyone there could recommend which oil to use as it seems to disappear. The receiptionist went to fetch their "expert" When he returned he said theres only one type of oil for petrol engines which is 10w 40 and there is only one type of oil for diesel cars and that is 15w40. I said no not Toyota oil - what about other makes and he told me as far as he knows they are the only types of oil you can get.

I have made my mind up never to have my car serviced or even touched by a Toyota Mechanic EVER