Mk 1 Avensis 1.8 7Afe Oil Consumption. Burning Oil

[Harry Carri]

Hi all,

My 1998 Avensis 1.8 ( 7AFE lean burn) has used oil for the whole time ( coming up three years) I have owned it. I change the oil every six months which is 4,000 miles ish. In that six months I add the remainder of the 5L of oil ( just over a Litre) bought to do the oil change as the level on the stick drops. By six months the dipstick shows oil at the minimum mark and the 5L container is empty and it is oil change time. I have added a flush to the oil prior to changing a couple of times. This oil consumption seems consistant and doesn't ruin the running of the car but clearly that oil is going somewhere.

So where is my oil going ?

I have no leaks. No signs of a gasket failure.

I do get white exhaust fumes. I did have an oily residue on the inside of the tail pipe so I think the engine is burning oil and the cat is collecting the greater part of it hence no blue exhaust fumes. I did give the car an Italian tune up and that did clean up the tail pipe fumes for a few days.

I am going to check the breather pipes. Does anyone know if the 7AFE 1.8 has a PCV valve ? as they can stick and cause oil to be burnt.

If the the breather pipes are clear and there is no PCV valve I am guessing I may have worn valve stem seals. Leaving the car to idle once I arrived at work (12 mile journey) and then giving it a rev produced white exhaust fumes each rev, I thnk that is a characteristic of worn stem seals.

I believe gunged up piston rings can also cause oil to be burnt. Opinions vary it seems, some recommend an Italian tune up to help free up and burn off the crud.

Some suggest Auto Transmission Fluid poured through the hole left once the spark plugs are removed to free up the rings, others say do not add a liquid to loosen the gunge as it could circulate and lodge in an oil way which would cause more problems.

Are there any other possible causes ? Are there further basic tests I can do at home ?

Opinions please.

I recently had a new cat fitted to the car so I would prefer not to fill it with half burnt oil and do intend to keep the car until the bitter end either from rust or a massively expensive mechanical failure. It seems the 7AFE in Celicas is known to burn oil but I haven't found many references to the lean burn 7AFE burning oil.

Thanks in advance.

Matt

[Konrad C]

Hi Matt, the 7AFE is not normally an oil burner, especially compared to the 1ZZ vvti engine. Yes I do give the occasional top up, but that is if the oil level has less than 3/4 on the dipstick.

You have probably mentioned the mileage before, but how much miles has it done?

What oil are you using, the brand and grade? I use Castrol Magnetec 10/40w. Changed roughly between 6-9 months depending on how the car is used. I will be changing my oil this week.

With mileage and age of the car comes how it has been used and cared for during it's life. The valve stem seals could be wearing. Is the exhaust clean or is there a hint of blue smoke? White smoke which disappears within a second of leaving the exhaust is condensation, I have seen proper white smoke and it thick, choking and leaves a long trail.

I will check on the breather system to see if there is a PCV valve.

Engine oil flush? Is your coolant okay - head gasket.

Oil leaks - have a look under the car, especially the oil cooler, pipes, and connections. Drips under the car. I always change the fibre washer to the sump plug. Copper washers do not work!

I will post any other info.

Konrad

[Konrad C]

Matt, I checked for PCV valve, and the closest I could find is on the big hose connected to the cam cover. A quick clean may help.

I changed the oil today and it really needed changing. I did a lot of short and stop/start journeys.

The car has done 1435xx miles.

Hope this helps.

Konrad

[Harry Carri]

Hi Konrad,

Thanks for your reply. In my post I wrote white exhaust fumes which on reflection is misleading. The fumes are always pale and light grey almost without colour.

In answer to your questions there is not a hint of blue in the fumes. Mileage currently 162,000 miles. I have covered 20,000 since July of 2012 so I accept the engine is no spring chicken and parts will show wear. Oil used currently and previously is Triple QX 5w 30 (Euro car Parts) Synthetic. Further back I used a 5w40 again from Euro. The coolant is clean and the rad was drained and refilled with new coolant a couple of months ago. No milky gunk then and now so gaskets healthy. The engine is oil leak free.

From start up this morning no fumes at all then regular pale fumes. If the valve stem seals were badly worn I would expect fumes from start up as the oil that has dripped past the seals into the cylinders is burnt.

As soon as I was home from work today I took a look at the two ventilation hoses / breather pipes. Both were clear. There was a small amount of oil in the end of the hose on the left (standing in front of the car looking at the block ) where it joins the valve cover and plugs into a grey plastic device which I reckoned was a PCV. I gently removed it from the grommet in the valve cover and it is a PCV bearing the number 15050 8FJ printed on its side. Gave it a wipe at each end which removed a bit of black grime and then gave it a gentle shake. There was a rattling noise from inside so I don't think it was completly full of crud but it must be 16 years old. I refitted the valve ( didn't manage to get it back in as snugly as it was) and the breather pipes. Ran and revved the engine to test. All held. Still have a bit of oily grime on the inside of the tail pipe.

Having had a surf on the web Toyodiy gave me part numbers of 12204 15050 for the valve and 90480 18001 for the grommet. Having most likely now got a slightly poorer seal by removing and refitting the valve into the grommet and given that the valve is most likely 16 years old I shall get a new valve and grommet and see if that reduces my oil consumption. Off to Toyota I go.

[Konrad C]

I looked at the breather hoses on my car and they were clear. The valve was a little dirty so I used brake cleaner and gave it a clean. It was not too dirty and not clogged.

When I started the car after cleaning, the car ran lumpy for a few seconds then settled down.

Another issue was the air filter was too loose. I simply remove the screws, sprayed WD40 and screwed down tighter. This seemed to remove most of the play. The box is designed to move/vibrate, but not excessive. When moving off the was a knocking, but I have not heard that since.

Still hate the exhaust, but it is not too offensive.

[Harry Carri]

Hi,

Thanks for the post Konrad.

Yesterday I gave the breather hose a dose of aerosol degreaser until it was clear fluid that came out at the other end. Let it dry and refitted it. I gave the valve a clean as well so all clean and dry when refitted.

This morning I phoned and ordered a new valve and grommet from the Inchcape Toyota due to arrive today so went home via the dealership. Unfortunatly the parts hadn't arrived and would be in tomorrow morning. The lady that took my order came out to appologise personally. Very nice touch and good service. Not to worry I had had a good day at work. Once home after a longer than usual drive I had a look at the breather hose at the inlet manifold end and saw a covering of oil on the port the hose fits over on the inlet manifold. Looks like some oil is getting past the valve and being drawn into the inlet manifold.

Time will tell once a new valve goes in.

[Harry Carri]

New pcv valve and grommet just fitted. I tested the old valve and found it wasnt always closing. I have added oil to bring up to the Max mark. I shall see how quickly it drops. I hope the new valve reduces the oil usage.

[Konrad C]

New pcv valve and grommet just fitted. I tested the old valve and found it wasnt always closing. I have added oil to bring up to the Max mark. I shall see how quickly it drops. I hope the new valve reduces the oil usage.

Hi Matt,

How much did the gasket and grommet cost? I could hear the valve clicking when I tilted the valve, as yours did. Does this means the valve should be working. How did you test the valve?

I assume the fumes can blow through the valve to relieve the pressure, but any oil causes the valve to close.

Your car has done nearly 19,000 miles more than mine. Hope fully the valve stem seals are okay. As I said before the car has had nearly two oil changes a year, from 2003 when I first took ownership. Not every year but definitely from late 2000's to this week. I did use slick 50 a couple of times - 2004 and 2009.

Lets hope the oil usage goes down.

Konrad

[Harry Carri]

Hi Konrad,

The grommet and valve were £30 from a main dealer. The lady discounted me £2 for my wasted journey yesterday.

When I took the new valve from it's packaging I blew into the larger end that fits into the grommet and the valve opened. When I sucked it closed instantly. Once the old valve was out I gave it a wash and blew into it sure enough it opened.Sucking not so easy without inhaling oily strange tasting residue but the valve wouldn't close reliably.

[Harry Carri]

As to how the valve is made up inside the case I have no idea. I guess it is simply open or closed . With mine sticking open I imagine on the induction strokes a mist of warm air with warm oil droplets would be drawn from the hose and into the inlet manifold. Little by little my oil would be sucked out. I guess the valve must be designed to allow air flow out of the rocker cover but be sufficiently weighted that the air induction at the inlet manifold doesn't open the valve.

On oil changes I am sure I have read ( Honest John ) that our lean burn engines benefit from six monthly oil changes. That is what I have done with both the Carina e and Avensis. I like having fresh oil in as the temperature drops in the Autumn and changing the oil spring time.

I haven't used Slick50 but I did consider it in the 1990s when there was a big marketing drive for it. A mechanic whose unit was next to the mechanic I used years ago had a car to be scrapped, drained the oil, added Slick50 only, no oil. He started it up and ran it until it seized. It took almost a tank of fuel before it died. Not very scientific but that stuff must be slippery.

[Harry Carri]

Well, I couldn't resist having a look after driving home at the inside of the hose and the port it fits over at the inet manifold end. Good news no oily film as there was with the old valve.

Yes I hope the valve stem seals are ok too. I think they are as I get no blue smoke at all, no fumes on start up.

Are you tempted to change yours Konrad ?

[Konrad C]

Well, I couldn't resist having a look after driving home at the inside of the hose and the port it fits over at the inet manifold end. Good news no oily film as there was with the old valve.

Yes I hope the valve stem seals are ok too. I think they are as I get no blue smoke at all, no fumes on start up.

Are you tempted to change yours Konrad ?

I might Matt.

My car has a clean exhaust with only the usual brief puff of white smoke in cold damp weather. I think the rubber may not be sealing due to age.

The engine has got back most of the smoothness since I re-aligned the exhaust.

I also with be cleaning my old disks, because they are 'warped', as is the replacements. On this forum, it has been said that the disks are not actually warped, but are contaminated. I will try and removed this contamination and see if the warp feel disappears.

Back on the oil consumption, I will be going to the NEC next Sunday so will see where the oil is blowing and I will see if I need to replace any other seals.

[Harry Carri]

Hi Konrad,

Might be worth changing the valve and grommet. I have taken the view that as I intend to the run the car to the bitter end I might as well have it running as well as possible and capitalise on good parts availability from dealer or breaker.

Good knowledge on the brake disks. I shall bear that in mind.

Happy motoring

[Harry Carri]

Sadly the new pcv valve has changed nothing. Perhaps I was being optimistic to think the valve could be responsible. Still it was a cheap and quick diy job so worth trying.

Here are details figures are in miles

12/3 oil topped up to Max on the dipstick at 162264

4/5 down to Min at 163647

Remaining oil added to bring to half way between Max & Min

31/5 down to Min at 164364

Oil being changed now.

So back of envelope and ball point pen gives.

1383 miles from Max to Min

Followed by

717 miles from half way to Min.

I think it is a litre from max to min. I will try to calculate as I refill the sump.

So is 1383 miles from max to min anywhere within "accepted" oil consumption?

[Harry Carri]

From filling it is just over a litre of oil to bring oil level from min to max on the stick so my figures seem true.