Oil burning

Minor but annoying oil burning problem with my 231

Nearly every time I start the car a bit of smoke puffs from the exaust, and no longer continues untill the next time I start it. What could be causing it?

Valve stem seals, when the motor isnt running its letting oil seep past the valves, when you start it the engine it burns off.

Valve stem seals, when the motor isnt running its letting oil seep past the valves, when you start it the engine it burns off.

Thank you, sounds like a lot of fun too :)

depending on the car it may or may not be hard to replace. Some people use an air adapter that screws into the spark plug hole and keeps pressure on the valve so you can remove the spring and pull the seal out, put it back together, all without removing the head... also can do similar to that with a rubber band or zip tie, if its an interferience motor you may be able to position whatever cylinder your working on at TDC and rest the valve on the top of the piston.

^never seen/heard what TSC is talking about but as a general rule valve work=pita

not complicated, just pita.

However it needs to be taken care of, i let if fly on my kart for a few months and next thing i know im relapping by valve seats because of all the carbon build up :(

You know valve steats are made to be reground....

yes, but it is a pain in the ass when all you have is a stick with a suction cup on it and some grinding compound.

They where fine the time that i rebuilt the motor before that (about 6months before ti started smoking) then it started smoking and i just kept adding oil instead of addressing the problem and 3 months later i had leaky valves and exaust comming out of the intake on idle and a milimeter of carbon build up on both valve seats.

Thats not grinding, thats lapping.

Issue:

I just bought a used car that turned out to be an oil burner (approx. 1 quart in 200 miles). The dealer has agreed in writing to rectify the problem within 4 days. What I am concerned about is how I will be able to verify that the problem is fixed. He seems amenable to having a mechanic shop do a wet/dry compression test to ascertain the source of the problem, and to show me the results. What I am concerned about is the possiblity that prior to doing the test he will load up the car with high viscosity oil and additives, which might throw off the test results. My questions are:

Is this a genuine issue? (IOW, can a burning problem this severe be temporarily masked in this manner, such that a compression test will have misleading results?)
In general, what can I do to verify that the car is genuinely fixed?

Thanks!

Issue:

I just bought a used car that turned out to be an oil burner (approx. 1 quart in 200 miles). The dealer has agreed in writing to rectify the problem within 4 days. What I am concerned about is how I will be able to verify that the problem is fixed. He seems amenable to having a mechanic shop do a wet/dry compression test to ascertain the source of the problem, and to show me the results. What I am concerned about is the possiblity that prior to doing the test he will load up the car with high viscosity oil and additives, which might throw off the test results. My questions are:

Is this a genuine issue? (IOW, can a burning problem this severe be temporarily masked in this manner, such that a compression test will have misleading results?)
In general, what can I do to verify that the car is genuinely fixed?

Thanks!
Sit there and watch the mechanic, make sure he doesn't do anything shady.

When the engine is burning that much oil, it's near impossible to cover it up, even with high viscosity oils or additives. Truth be told, the only way for your dealer to really fix the problem is to swap the engine with a different [better running] one, or to replace the piston rings.

Thanks a lot.

Are you saying that this much oil has to be the piston rings and cannot be the valves? I was hoping it was the valves. I can't imagine the dealer will be able to repair the rings for the amount of $ that he is getting for the car. My understanding is that the valves are relatively inexpensive, especially for a guy who has his own mechanic. So if you are in fact saying that this amount of burning rules out the valves as the culprit, please confirm this.

(Actually watching the dealer is not a practical option under the circumstances.)

It could also be the valves, but im thinking it's a combination of the valves as well as the rings that are letting oil past. Using 1 quart of oil every 200 miles is a huge amount as far as oil consumption goes, however replacing some of the valvetrain components might correct the problem. I don't think that a simple valve adjustment will fix such a huge oil burning problem.

The compression test will determine if it's the valves or the rings that are at fault (or both). Then you/the dealer can decide what to do from there.

That much oil is not going to be valve seals leaking. Unless all the seals were removed and the valve guides are whored out.

that much oil the engine is running halfway diesle :D

The plot thickens. I just got a call from the dealer and he says he had his mechanic (an indepent mechanic but one with whom he does a lot of business) did a wet/dry compression test and it shows no oil burning at all - engine compression is fine. He is going to give me the write-up from that mechanic.

Now the facts that I know are that I changed the oil myself last Sunday and the next day it was about 0.4 quarts lower and the next day about 0.5 quarts lower. Saw this with my own eyes. Could I be wrong? My mechanic also identified an oil leak in the valve cover gasket (the dealer replaced this) but my mechanic insisted there is no way that amount of oil could be leaking from that source.

I think to be safe I should change the oil tonight to get rid of any possible additives or heavier oil (the dealer claims he used 10W40 and no additives) and then have another compression test done. But this dealer knows I've had a mechanic look at it, and knows I will bring it back to the guy. So I wonder if there's possibly some trick I'm missing?

The whole thing is weird.

I think your just imagining things.

I hope so.

I called up his mechanic who ran the test and spoke to him. He said the compression test showed compression of 140, which he said is normal, and that it's pretty evenly distributed. He said he could not rule out valve seal problems with this test, however.

I have a Haynes manual for the car (2000 Prizm/Corolla) and if I'm understanding it correctly it says the compression is 218, with a minimum of 145. Which is correct?

140 sounds a little on the low end. is it smoking or is it just loosing oil? You are very good if you can notice the differnce in 1/10 of a quart... maby your just parked on a hill?

I've not mentioned noticing the difference of 1/10 of a quart. To clarify, it was low by 0.4 after one day and an ADDITIONAL 0.5 the next day, or about 1 quart in total. I've not been able to see any smoking. I will try to check again more closely, but there's certainly not anything easily noticable.

I got the actual receipt from the mechanic. He writes the following:

"Engine Compression test
All 4 cylanders have 140 PSI even, Dry
Wet test was 165 PSI
No oil found on the spark plugs."

Again this mechanic believes that these test results ruled out worn piston rings - he told me on the phone that if there is indeed oil burning it must be faulty valve guides. He said that 140 is an OK number and that in any event the more significant thing is that the cylinders did not vary by much.

I would have thought the indication is more like worn piston rings, based on the difference between the wet and dry pressures. But I am no mechanic.

I picked the car up from the dealer today, drove it about 50 miles, and lost about 1/5 of a quart, which is in line with my previous measurements.

So what's the assessment, based on losing a quart or so in 200-250 miles, dry/wet compression readings of 140/165, and no oil on the plugs? Taken all together, is it piston rings, valve guides or something else? And can anything be ruled out?

Take it to another mechanic (preferably a name brand franchise like Firestone, Midas, etc). Have them do the same thing - compression test/check plugs. AND have them also put it in writing. If the other mechanic says something different (that there is oil burning) then show it to the dealer and shove it in their face.

I don't think there's much you can do legally here but it might make your dealer have a change of mind and actually fess up to their lies. (assuming they were wrong)

Actually I'm on extremely solid ground legally, because (after disputing the credit card payment and threatening a lawsuit) the dealer signed an agreement to fix all issues with the car (there were others, of lesser import) "to [my] satisfaction" or refund my money. So if I don't think it is fixed then it's not to my satisfaction, and the deal is off. Theoretically I could weasel out of the whole thing in this manner, regardless. But I'd like to play straight, if the guy is making a good-faith effort to play straight with me.

So the question is really a matter of interpretation. Assuming the mechanic's numbers are accurate, is his interpretation accurate?

The dealer wasn't in when I picked up the car, but he had written on the mechanic's report that he would replace the valve seals if the car continued to burn oil. While I'm a bit tired of dealing with this car, if I believed the mechanic's assessment that any oil burning had to be the result of valve seals I would be inclined to just bring it back again and let him fix the seals. But if I think it is most likely - based on the evidence above - the piston rings, then I am just going to return the car and move on. So I need some educated opinions on this.

Take it to another mechanic (preferably a name brand franchise like Firestone, Midas, etc). Have them do the same thing - compression test/check plugs. AND have them also put it in writing. If the other mechanic says something different (that there is oil burning) then show it to the dealer and shove it in their face.

I don't think there's much you can do legally here but it might make your dealer have a change of mind and actually fess up to their lies. (assuming they were wrong)

ive found that its better to take it to an independant mechanic that has a good reputation than to a midas or w/e. Just like its better to go to an indpendant parts store with a good reputation than to Napa or Autozone...or at least that is around here. Maybe its because i've know the daughter of pete oilin's autoparts for 6 years...i dont know :lol: