Brent 89-GT

As much as I hate to publicly admit my car has a problem, I decided I would never try to sell it to anybody in its current state anyway. That brings me here looking for help and opinions on what might be wrong with my car.

It developed a fairly dramatic increase in oil use this fall before I parked it. Used to be I could go 5000 miles between oil changes and not have to add any oil. I would use maybe half a quart. Now it is using a quart every 500 miles or so. It wasn't a gradual increase, it happened pretty suddenly.

I checked the plugs for evidence. The front one, passenger side, was covered badly in a light colored ash. My assumption is that this is the oil burning cylinder, but why? The plugs on the drivers side all look good. The back two on the passenger side also look very good. The second one on the pass side had some ash.

I guess my choices are from two seemingly rare failures. Is it valve stem seals failing? Is it a headgasket? There was no coolant use, no oil/coolant mixing that I have found, no sweet tasting exhaust like my 951 had a couple of times. The car runs fine and I don't see it smoke from the drivers seat. No leaks on the ground of any fluids and it has about 95k miles.

I need suggestions on how to proceed. I hate looking at it in the garage, wanting to take it for a spin but knowing something is wrong.

Gretch

I guess if it was me I would start with leak down and compression tests.......

heinrich

Brent I second what Gretch said, and add that you must stop driving or running the engine now. We had a local car hydrolock under the same conditions you describe, from oil in the cylinder. it's a downhill slope. He was using a quart every 100 though. Anyway, cylinder one (front-passenger side) will likely be the one with the problem. It may be a broken ring, disintegrted valve seal, who know. But just for the fun of it, take a look after removing the MAF, inside the throttle body. See if there is excessive oil pooling there.

worf928

I would thoroughly check the engine - under, over, and around - for oil leaks (e.g. Pan gasket, breather hoses under the intake, etc.) before contemplating the possibility of internal engine problem.

heinrich

DOH!! Dave took a reality pill this am YES!

heinrich

Oh wait ... Dave is always realistic.

Brent 89-GT

It is definately not leaking the oil. No puddles anwhere it has been parked and I have been underneath it with the flashlight. I have also pulled the air cleaner and looked down through the MAF sensor, all looks normal in there. I think the ash covered plug identifies that cylinder as the likely problem.

I can easily do the compression test, and will this week. Leakdown seems to be a more complex procedure and hauling the car on my open trailer in the winter is something I am trying to avoid.

I haven't been driving the car for a while now, pretty much since I discovered the problem in late Sept. Hopefully it is a valve stem seal. Not that I am excited about removing the valve cover, I understand that is awful, but it sure beats a headgasket or broken ring. Thanks for the ideas guys, I will report back after the compression check.

Jim_H

Don't forget, dohc...

ErnestSw

Removing the valve covers isn't really all that hard. You've just got to hold your mouth the right way and make sure you say the magic words. (I won't repeat them here). It also helps to remember that you have to bend/move the front lift point out of the way on the passenger's side.

hacker-pschorr

My 81 had a #1 plug that looked like it was rubbed in margaritta salt after only a few hundred miles. My oil consumption was not as bad as yours though. The rest of the plugs looked anywhere from ok to somwhat oil soaked. Ended up being valve guides / seals.

jeff jackson

if its "consuming" oil at that rate...it "should" be producing some prodigious tailpipe smoke, and fouling spark plugs ...constantly. Is is smoking badly ??? Do the compression and leakdown tests to determine cylinder and valve condition.... You'll know right away whether you've isolated the cause, (and hence the cure)...or whether you need to delve deeper. If its NOT smoking badly...and constantly.. It "could" be a leak all right...front or rear main seal, or some other pressurized location that would only be evident when the car is running and the oiling system pressurized. If it IS the valve seals...the valve guide is likely shot as well on that cylinder, (whatever caused the seal to fatigue prematurely...most certainly affected the valve stem guide as well) and replacement of the seal alone...will result in a very quick return to the oil consumption problem.

worf928

Check the under-intake valley between the heads. You will need an inspection mirror and flash light. Just be da@mn sure it isn't a simple leak before you dive in to the valves. Oil cooler. Pan. Rear main seal. The RMS can leak a lot of oil and not be too obvious. Stick your finger in the inspection hole on the clutch cover and swirl it around.

The absence of a puddle in your driveway does not indicate that you don't have a leak.

EDIT: Doh! '89 does not have a separate oil cooler like the '90+.