Well.. The turbowagon is still burning a quart of oil every 400-500 miles. At least I know it's not the turbo seals because I rebuilt the turbo. I'm wondering if I can pull the head and refresh it and make the problem go away. Car has 235K on it. Will a leakdown test tell me if the oil is migrating past the rings? If it's not, would I be reasonably safe in assuming the oil is leaking past the valve guides or seals? I've got no blue smoke that I can ever see either accelerating or decellerating.

As always, thanks for any responses,
--
Bob W.
'91 744T 173K
'82 245Ti 238K
'81 245 GLT, non-turbo 275K
'67 122 wagon

What do your plugs look like? Normally (on SB Chevy's anyway...) valve guides/seals will give you a good cloud when starting up in the morning as oil leaks past them into the combustion chambers.

My wife bought me a 69 MGB project car for my birthday, a long time ago, that had sat for several years and it burned oil something fierce - smoked like crazy. I put a couple of cans of Berryman's B-12 in the crankcase, let it idle for about 45 minutes, changed oil and filter and oil consumption decreased significantly. Went from killing mosquitos to burning about a qt every 1000 miles.

I guess the oil rings must have been gummed up/stuck and this stuff loosened them up or something. Don't know if this might help you or not.

Good luck,

Justin B.

I agree with everything John wrote. A leak-down test is not likely to be helpful.

At your oil consumption rate, you should be seeing some blue smoke at some point while running.

On some cars,hI would suspect a leak that was not soiling the car, so you don't notice a puddle in the garage. On Volvos, that doesn't happen. The leak fills the splash pan and generally paints the bottom of the car, leaving plenty of evidence on the garage floor.

Blue smoke during deceleration suggests intake valve guide problems, blue smoke while accelerating suggests bad oil rings. Oil leaks past the exhaust valve guides would go out the back as tiny droplets, usually causing the rear of the car to get dirty quickly, unless the catalyst is still working, in which case, the oil will burn in the cat and give you uniform blue smoke, but perhaps not enough that you are noticing it yet.

A leakdown test will not tell you if oil is getting past the rings. You can have an engine with good leak down test results that uses plenty of oil. I have personal experience with a non-Volvo engine in this area. Compressed air leakage past the rings is not indicative of oil consumption, nor are high leak down test readings indicative of low oil consumption. A leak down test is great for spotting bad valves, and they will let you know the relative condition of the cylinders with respect to each other.