Mix different type of oils

[brainii]

So I bought one of those cheap oil pumps and some cheap oil and will be soon doing an oil change myself.

I've always put 15w40 mineral oil in my 1st gen Auris.

But, I've also got about 1 litre expensive fully synthetic 5w-30 oil leftover from a different car/oil change (oil about 1 year old, and in an opened 5l bottle, stored indoors).

Can I throw it in the mix safely?

I'm thinking if anything, this will improve slightly the overall quality of the oil.

thanks

[Perfection]

This is definitely effective cost driving.

I can't recommend, but from my experience I never had mixed mineral and synthetic. I had mixed different brands but all synthetics. I.e I had some left over of about 1lite of Shell and 5 litre of new Castrol. 

[Red_Corolla]

What car is it for? Read the owners manual and make sure you've got the recommended grade. 15w40 mineral isn't going to be good enough for anything built within the last 10 years. Mixing different viscosities is OK as long as they're both within spec for the engine, but I personally wouldn't be using any mineral oil in this day and age, not on a modern engine.

I wouldn't recommend extracting the old oil with a pump, either. It takes longer and doesn't get to the nasty stuff sitting in the bottom of the sump. Much easier to take the plug out and drain it - you'll be going underneath to change the filter anyway, right? I can tell that you want to save money, but don't even think about skipping the filter!

[TonyHSD]

Mixing oil brands and types can be ok if within the specs of the car although not ideal but in your case adding 5w30 into 15w40 it’s not gonna improve anything.
Actually the correct oil for your car is 5w30 not 15w40.
In todays applications except door hinges or bicycle chains I don’t see really in what else 15w40 can be a good choice. You can buy good quality 5w30:oil at good price and use in your car. 

[Xanadu_999]

6 hours ago, brainii said:

I've always put... mineral oil in my 1st gen Auris.

At the very least you would be wise to use a semi-synthetic oil, even my 30+ year old Celica gets treated to that each year.

[brainii]

It's for my 2007 Auris.

I've ALWAYS been using standard 15w40 and the car (and all other similar age cars) has been fine ,this oil is recommended by all mechanics and even what most dealerships use for cars of that age in Cyprus.

Not wanting to debate oil viscocity, we get really hot weather here, right now temp is around 30c and its 7am.

I change the oil twice a year (regardless of miles which are pretty low, usually 2000 km every 6 months, filter is changed once a year). I plan to use the pump every other oil change. The other oil change will be done at bottom of the sump and new filter of course.

 

 

 

 

 

 

 

[Eddiefh]

30 degrees at 7 sounds bliss 

[brainii]

4 hours ago, Eddiefh said:

30 degrees at 7 sounds bliss 

until it's 1pm and its 43c 🙂

 

[Red_Corolla]

Engine oil operates at 100 degrees. So warm climates allow for a bit higher cold viscosity, but it still has to thin out enough when it's warmed up.

For the 2007 Auris, I think the regime is absolutely fine and the engine should last a long, long time. It was the 2022 Corolla I was worried about - that one will require 0w20 or thinner. Toyota have started to use 0w8 in the American market.

[TonyHSD]

I have stopped trusting mechanics what they say long ago. 
Check owners manual, car labels, tech literature etc and see what was the original oil type and viscosity for this car engine and stick with these no matter where you live. 15w40 mineral oil is not ideal in your case as mineral oils tend to break easily when at high temperatures, they form soot and other particular matter , block piston rings, hydraulic lifters, and can starve the engine at cold temperatures. 
Using wrong type of oil and changing twice might sound like a good deal but using the correct oil and change once a year within the recommended miles is better option, and changing the oil without changing the filter is also not ideal. 

[Eddiefh]

5 hours ago, brainii said:

until it's 1pm and its 43c 🙂

 

I used to live in dhekelia 

 

5 hours ago, brainii said:

until it's 1pm and its 43c 🙂

 

 

[Hadrian1]

As I stopped doing my own oil changes about 40yrs ago, back in the days of the original Duckhams.

I can't offer any advice.

Mixing oils does seem rather extreme though. It depends on how much you value your car.

[ziauris]

Lowest I would go is semi-syn and stick to 1 yr changes rather than all the hassle with crappy oil and 6/12 oil changes!

[Parts-King]

3 hours ago, Red_Corolla said:

Toyota have started to use 0w8 in the American market.

and the UK Market, New Yaris run on 0W 8. 

[TonyHSD]

I have been experimenting with oils , additives, coolant, screen washes etc and although if mixed two different types of any of these won’t cause any harm , at least not immediately it is definitely not a good practice. 
1. Engine oil together with transmission fluid if two different types and viscosity are mixed can cause foaming which can increase friction, temperature and wear on the moving parts. 

2. Different coolant types can lead to acidic solution and wear on internals, water pump seals, bearings, radiators . 
3. Different screen washes can form fungus and really bad smell. 
Anyone free to do anything and no immediate harm will happen. What is best for your car it’s totally different situation. I found through the years and many cars owned, flipped, or serviced that best practice is to stick to manufacturer recommended types, viscosity and intervals. Use only original transmission fluids and coolant. Brake fluid and engine oil can be high quality aftermarket together with screen wash. 

car parts - Toyota does not like aftermarket, even plastic clips , t(r oem Toyota stuff it’s the way to go. 
Try to buy everything original if possible with exception of filters , tyres, bulbs. , these could be found even better price quality ratios. 
Wiper Blades Only Denso hybrid- anything else it’s not up to the job. 
And another tip for long and trouble free ownership- try to refrain from any modifications, stay stock and only change anything if you are 100% sure it needs changing. To the hybrid owners if you ever need to replace hybrid Battery, just buy new from Toyota. Your car will thank you, 👌

[ziauris]

5 hours ago, TonyHSD said:

I have been experimenting with oils , additives, coolant, screen washes etc and although if mixed two different types of any of these won’t cause any harm , at least not immediately it is definitely not a good practice. 
1. Engine oil together with transmission fluid if two different types and viscosity are mixed can cause foaming which can increase friction, temperature and wear on the moving parts. 

2. Different coolant types can lead to acidic solution and wear on internals, water pump seals, bearings, radiators . 
3. Different screen washes can form fungus and really bad smell. 
Anyone free to do anything and no immediate harm will happen. What is best for your car it’s totally different situation. I found through the years and many cars owned, flipped, or serviced that best practice is to stick to manufacturer recommended types, viscosity and intervals. Use only original transmission fluids and coolant. Brake fluid and engine oil can be high quality aftermarket together with screen wash. 

car parts - Toyota does not like aftermarket, even plastic clips , t(r oem Toyota stuff it’s the way to go. 
Try to buy everything original if possible with exception of filters , tyres, bulbs. , these could be found even better price quality ratios. 
Wiper blades Only Denso hybrid- anything else it’s not up to the job. 
And another tip for long and trouble free ownership- try to refrain from any modifications, stay stock and only change anything if you are 100% sure it needs changing. To the hybrid owners if you ever need to replace hybrid battery, just buy new from Toyota. Your car will thank you, 👌

 

I know where you're coming from but ....I used to buy the Toyota coolant but £10 for 1L of 50:50 water:coolant really started to chafe as the water pumps on Auris are !Removed! and leaked it out not long after topping up. I've replaced 2 water pumps on Auris and its only done 100k. If I bought original pump and coolant the Auris would not be worth keeping. I used Mannol G12+ red or AF12+ coolant for £12 for 5L - seems very similar to Toyota SLL coolant at a fraction of the price and made the repairs/servicing bearable.

[ziauris]

5 hours ago, TonyHSD said:

I have been experimenting with oils , additives, coolant, screen washes etc and although if mixed two different types of any of these won’t cause any harm , at least not immediately it is definitely not a good practice. 
1. Engine oil together with transmission fluid if two different types and viscosity are mixed can cause foaming which can increase friction, temperature and wear on the moving parts. 

2. Different coolant types can lead to acidic solution and wear on internals, water pump seals, bearings, radiators . 
3. Different screen washes can form fungus and really bad smell. 
Anyone free to do anything and no immediate harm will happen. What is best for your car it’s totally different situation. I found through the years and many cars owned, flipped, or serviced that best practice is to stick to manufacturer recommended types, viscosity and intervals. Use only original transmission fluids and coolant. Brake fluid and engine oil can be high quality aftermarket together with screen wash. 

car parts - Toyota does not like aftermarket, even plastic clips , t(r oem Toyota stuff it’s the way to go. 
Try to buy everything original if possible with exception of filters , tyres, bulbs. , these could be found even better price quality ratios. 
Wiper blades Only Denso hybrid- anything else it’s not up to the job. 
And another tip for long and trouble free ownership- try to refrain from any modifications, stay stock and only change anything if you are 100% sure it needs changing. To the hybrid owners if you ever need to replace hybrid battery, just buy new from Toyota. Your car will thank you, 👌

On screen wash, I think the EuroCarFarts ones left an oily film on my car and smeared the screen. Either it was poorly manufactured or some nasty, vindictive fck3r at Toyota Hudds intentionally put a few drops of oil into by washer reservoir to mess with me when I took it in for a recall. 

[brainii]

This is a turning out to be a very interesting post.

A couple of points.

1) There's a youtube video of project farm mixing 10 different oils (brands and types). He then analyzed the oil. No issues found.

2) I personally believe that (in my cars, which are low mileage, and in these environmental conditions) it's important to change oil twice a year (even if it's "lower" quality) rather than once with a more expensive oil. People claim that over time moisture and impurities get into the engine / oil breaks down and that's much worse for the engine.

3) The 15w40 oil is not the wrong oil for the car. It might not be the "best" but is certainly not the wrong type. In fact it's right there in the original owners manual chart (there's a range of oils).

4) Traditionally, in hotter climates (middle easy, mexico, australia etc), car mechanics and car manuals use thicker oils.

5) There's a huge debate online about the constant thinning of newer oils, for newer engines. A lot of people claim that this thinning has nothing to do with engine longevity and everything to do with achieving lower emissions / better economy in a lab (In Europe this is very important as manufacturers wouldn't be able to sell the cars at all, if they didn't achieve these standards, which are constantly becoming stricter).

6) I personally believe manufacturers couldn't give 2 rats ubiks if your car broke down after the warranty period, or if it broke down at 200k km instead of 300k km or at 10 years instead of 20 years (most ppl get rid of the cars long before then anyway).

7) On a final note, on my 2022 Corolla, I'm using 5w30. Can't even find 0w-16 locally. When I asked the Toyota dealership about it they said they never use this oil for any new car and don't even stock it, and the lowest they use is 5w-30 and that's the right oil for Cyprus, according to Toyota Europe's instructions. They did say they can bring me the oil from the UK on a special order (at a price of 20 euro per litre+VAT).

 

These are just some thoughts.

[xrhstosgr]

 

Hello it is possible to mix different types of oils but ALWAYS with the same viscosity. What you want to do is like throwing synthetic oil in the garbage.

[xrhstosgr]

8 hours ago, ziauris said:

 

Ξέρω από πού έρχεστε αλλά .... Αγόραζα το ψυκτικό της Toyota αλλά 10 £ για 1 λίτρο νερού:ψυκτικό 50:50 άρχισε πραγματικά να φθείρεται καθώς οι αντλίες νερού στο Auris έχουν αφαιρεθεί! και διέρρευσε λίγο μετά τη συμπλήρωση. Έχω αντικαταστήσει 2 αντλίες νερού στο Auris και μόνο 100 χιλιάδες. Αν αγόραζα γνήσια αντλία και ψυκτικό, το Auris δεν θα άξιζε να το κρατήσω. Χρησιμοποίησα ψυκτικό Mannol G12+ κόκκινο ή AF12+ για 12 £ για 5 λίτρα - μοιάζει πολύ με το ψυκτικό της Toyota SLL σε ένα κλάσμα της τιμής και έκανε τις επισκευές/σέρβις υποφερτές.

Touota Creece in the country I live in gives a 5 year no mileage warranty for the antifreeze (SLIC) I changed in my car

[brainii]

here is another exhaustive video comparing thin vs thick oils:

 

data reveals that thinner oil gives slightly more performance but also a lot more wear.

i keep my cars 20+ years so id take longevity/reliability over performance anytime