excessive oil use

Thank you. This is a DOHC engine, 16 valve engine with bucket cam followers ... which in themselves behave like an umbrella to shield away oil tossed from the cam shafts. Of course, there are oil seals on the guides. BUT ... the reciprocating movement of the cam buckets themselves do create a pumping turbulence very close to the valve stem sealing lip.

-Philip

Another condition that will contribute to abnormal oil consumption is ... compression rings that have lost a high percentage of their tension against the cylinder wall. At idle, there may well be little blow-by pressure present. BUT ... stick your foot in the throttle and wing the rpms up high .... and for that time, blow-by is way above normal. Excessive blow-by under this condition will push the oil ring rails away from the cylinder wall ... allowing oil to get past the compression rings ... and exit out the exhaust. This would make exhaust smoke only under acceleration. Now with a catalyst or two on the exhaust, it is very doubtful there would be smoke sufficient to see were you following this Corolla (ie, following him up a freeway onramp). How could this happen? The engine got very overheated at some point in its past.

-Philip

Is it known how long this rate of oil consumption has be the case? Speaking for my own 2003 Corolla with the same engine and 43k miles, my engine consumes about 1/3 quart of 10w30 Mobil1 per 5,000 miles.

-Philip

The OP didn't mention how long the engine has been consuming that much oil.

Okay, but HOW?

The explanations you posted earlier suggest that the crankcase pressure will rise and force oil out of the seals, wheich results in puddles on the ground. Our discussion is that the oil is going out the tail pipe, and I'm having trouble resolving how that might happen. I suggested that it is plausable that oil can get past the rings in that case, but that theory was specifically shot down. But, we still have a car that is using oil, and the report is that it is burning out, not draining out.

See WHAT above? This is the part I am missing. You, and others keep saying see above, but there is no explanation above to look at.

I guess I am asking the route that the oil might take because the links previously given suggest the route is through the outside and onto the ground.

I'll be the first to admit that I am not a professional mechanic, but I've managed to do a pretty good job keeping my fleet on the road for 30+ years, and that statement is contrary to everything I have ever heard. Perhaps my choice of words -- suck oil past the rings -- is a poor choice, but the fact remains, high engine speeds are known to result in oil consumption in passenger cars. Maybe I haven't got a clear understanding on where the oil goes in these conditions, or how it goes there, but it's clear that the oil goes. It occurs to me that it ought not go as quickly as the OP says, but it goes.

PLEASE DO. That is what I've been asking for a couple of days now. How? That's been my question. I thought I had it down, but you guys are saying I don't, but have not pointed out where I went wrong. I'm ready to learn, tell me where I'm not getting it.

I hear what your saying, but Ray posted a link that specifically refutes that. The link says that a clogged PCV will result in increased crankcase pressures, and this will lead to oil leaking to the outside of the motor.

Let's move beyond this for a moment. If there is a clogged PCV, and the gases use the parallel path, and these gases can contain enough oil mist (for lack of a better term) to show up on the back of the trunk, and manafest itself as a quart per 1000 miles of oil use?

Now we're getting somewhere.

It's not my motor to test.

snip

Ok. Let me diagram it for you in elementary terms. Consider how many paths there are for oil to leave the the engine and exit the exhaust pipe.

-Philip

First of all, burning a quart of oil every 1,000 miles is not THAT fast. The Toyota Warranty Policies and Procedures manual that dealers must follow when submitting warranty claims says that up to 1 quart per 1,000 miles is acceptable, although I personally wouldn't be happy with that kind of oil consumption.

Philip gave what I thought was an excellent description of what is going on, but the description does assume that one knows how the PCV system works. Check out Page 2 of this link

The reason for ventilating the crankcase is that some blowby gases will always make it into the crankcase, even with properly functioning compression rings.

Pistons generally have 3 rings - the top 2 look almost like springs and are the compression rings. They seal most, but not all, of the combustion gases in the combustion chamber. What leaks past the compression rings is blow-by.

The bottom ring is made of cast metal and is the oil ring. It is like a circular squeegee and when the piston is moving down, it wipes the oil off the cylinder walls.

The cylinder walls are lubricated by the oil thrown up from the crankshaft. At higher RPM, the crankshaft throws more oil. The oil rings don't keep up with the extra oil and leave more oil on the cylinder walls, which gets burned in the combustion process.

He didn't say how long this has been going on, and your rate of consumption sounds like what I would expect. The OP is using oil at about 15 times the rate yo are using it.

. Are you sure it is burning and not draining?

I'm am sure there are no engine leaks. Someone mentioned ash on the plugs, I took them out to do the compression check and they all had a light coat of ash on them, no oil though. Does this change anyone's opionion on what may be wrong? The vehicle is not driven hard. George

I have a 1995 Toyota Corolla with the 1.8L 7AFE engine >>> The manual recommends 5W30 for the 1.8L(mine) but 10W30 for the other 1.6L 4AFE engine.

Which is best? Performance-wise? MPG-wise?

Should I change the oil type in the winter? I live in IL/IA.

Symthetic, blend, or regular oil?

In theory, the 5W-30 will provide better performance and fuel mileage. In real-world usage, the average driver would not notice the difference.

The manufacturer recommends oil viscosity based on expected ambient temperature ranges. In the midwest, 5W-30 shouldbe fine year-round.

The synthetic vs. conventional motor oil is a debate that has been raging since the introduction of synthetic oil. Toyota does not recommend extending oil change intervals with synthetic oil; in other words, they recommend changing it as often as conventional oil. If you do so, your oil change costs will probably double.

In theory, synthetic oil will outperform conventional oil but if you follow the manufacturer's recommended oil change intervals, then the average driver will not be able to discern the difference.

Full synthetic is best for performance and mileage, however, it isn't the best for economics. I've used Mobil 1 for nearly 30 years, but I don't use it to save money, I use it for the much faster starts in below-zero winters.

Matt

Yes, the only real noticeable difference is in very cold weather. At temps below zero the difference in cranking speed between synthetic and dino oil is very noticeable.

MAtt

Yes the tighter toleraance cam after they started using 5w30 oil. Even today you will still find 10w30 in a GM owners manual and I use 10w30 in my 2000 5.7 except for a few months in the winter because I average about 5psi or so more oil pressure with 10w30 than I do with 5w30 and my truck works hard sometimes.

Better crack it open again because GM has changed tolerances in new modular engines for the older designs (some tighter and so looser) to add in production and Chilton is not the bible on them and their specs are no always correct. I try to use factory manuals when I need to be exact.

Also on 5w30 vs 10w30 there is a difference at all temps. 5w30 has a lot more VI in it to modifiy the oils viscosity properties and it does not track evenly with 10w30 are warmer temp and will thin out more above 210 than 10w30 will. ALso the VI actually takes away from the oils lubrication properties somewhat and the more there is, the more it takes away. It is a trade off of sorts so striaght 30 will be better at high temps than 10w30 and 10w30 will be better than 5w30 with Dino oil and there is no escaping this. YOu must remeber that SAE weight ratings are not absolute because 10w30 rated SYN oil will flow a lot better at minus 30 than 5w30 Dino oil will.

"Tighter tolerance cam?" Rubbish.

With 5w-30 oils cam a new standard for less ZDDP anti-scuff agent in all passenger car and light truck motor oils. This put traditional push rod engines having flat tappet cam followers and some over head cam engines with rocker arm followers in jeopardy. So ... these engines were refitted with roller followers.

-Philip

Look up friend. Find the passage where I state "engines that have been in production for a decade or two." Also notice I specifically call out "Motors Repair" manuals ... not Chilton. You exhibit a read comprehension deficit.

This false in any meaningful degree after oil temperatures rise above 25 degree F.

snipped the drivel.

Academically speaking. But again, not to any significant degree that shows up in engine component wear.

-Philip

Well, the oil has to be either burning or leaking on the driveway. If leaking, you would know. If burning at the rates you suggest, the plugs should be wet with oil, not to mention the possibility they would be ashy.

Since you are convinced the oil is burning and not leaking, then the options are rings, valve seals, and PCV Valve, or a combination of all of these. Given the relative low mileage, I'd go cheap and easy and replace the PCV valve, and take a close look at the PCV hoses and associated plumbing. If you don't see any problems here, then you will need to go inside the motor.