My car has been burning oil (at least 1qt per 2500 miles) since around 35000 miles. I am now at 95000 miles.

I recently changed the plugs after a 50000 mile interval and the electrodes were covered in gray soot in all 6 cylinders, but the threads were dry and there wasn't any oil in the holes where the plugs go. The car has never leaked oil and a compressions check showed all cylinders to be fine. There is always quite a bit of black soot in the tailpipes, something that I never saw on our Z, so oil is being burned.

About 3000 miles ago when I changed the plugs, my mechanic also cleaned up the valve covers on both sides of the engine. They were covered in oily soot. After 3000 miles I noticed that the drivers side valve cover was so covered in oily soot that it seemed to have pooled near the coil packs at the low point of the valve cover. The passenger side was still clean.


So, my question is: where is all of this oil going and what can I do to stop it? I already have a catch can that does capture a lot of oil, but obviously this is not the problem.

Any thoughts would be appreciated.

 

Jeez, I had never thought of that


My situation seems to be different than any others I have read about: I don't have a rev up and it doesn't seem to be my valve covers. That is why I tried to be as detailed as possible in my description.


Have you read anything that I haven't and could share some of your expertise or point me in the right direction?

 

If its not leaking then its burning. And from the description you gave of your plugs I would assume, burn. Just because its not a rev up doesn't mean it can't have the same problem. Do you run synthetic oil? And if so how early did you switch to it?

 

i would verify that the PCV system is working properly.

 

Looks like you have a valve cover leak by your description - mechanic messed up on that side. Need to redo it. Improper PCV operation will lead to crankcase pressure and seal leaks, which you don't seem to have, but it's a 5 min swap of a $12 part.

Oil that is being burned is going past rings or past the valve seals. That is all. 1 qt per 2500 miles isn't so bad. Just fill up a qt, what monthly at most?