I need help in diagnosing where I am losing oil. Since rebuilding the engine last year, I am losing about a quart every 2,000 miles. I have absolutely no external leaks. I have had my oil analyzed and there is no antifreeze contamination. There is no oil in the coolant either.

I suspect I am losing it past the rings or valve seals but I have no visible oil smoke when starting the car after sitting for a period of time or while running. I did have a problem with high hydrocarbons in the exhaust during last state inspection.

During the rebuild, everything was replaced, new pistons, rings (Total Seal gapless), valve seals, etc. Heads were reconditioned, valve guides checked and in tolerance, etc. How can I diagnose where the oil is going without another tear down? Any ideas? Is it possible I need to use a thicker oil? I am currently using 5W-30 which I have used for the last 400,000 miles in this car.

 

Do a compression test followed by a leakdown test..

Check the PCV system..

Pull the oil cap off and run the engine...do you get any smoke out of the valve cover?

 

For the oil cap, I'll check for puffing or smoke.

What am a I looking for in the PCV system? fyi - I installed an oil separator in the pvc hose when I rebuilt the engine. It collects a little oil but nothing that would not have been burned off in the intake anyway.

I need to get a leak down tester but can do a compression check right away. Will do this over the next few days. I need to finish an oil pan replacement on a T-bird that is in my garage first.

I planned to visually inspect the plugs for signs of oil but not sure if that will tell me the source. Will do this when I do the compression test and leak down test.

Thanks for the ideas. Please keep em coming.

 

You check the PCV system t make sure it is flowing freely. A blockage increases crankcase pressure and can force blow by.

 

That is interesting. I replaced the pcv valve and I know the lines are clear. But maybe the filter in the oil separator is clogged. I will check that. Good catch because I did not clean that when I rebuilt the engine. Will let you know what I find. Thanks.