I've found a lot of posts about smoking turbos, but I haven't come across a definitive answer to tell me how to confirm it's the turbo and not valves or rings. Blue smoke after warming up, usually only noticeable at idle or in stop and go traffic. Compression is fine.
TIA,
Ed


2001 A4 1.8T

 

Having the same problem here. any help would be appreciated. just replaced valve stem seals and still smoking. anyone had this problem and fixed it?
-Mike

 

boost gauge is the easiest way to maintain your turbo

 

Valves or rings would more likely cause smoking under boost, not idle or startup. Valve stem seals are usually the culprit for your conditions, but the most smoke usually comes at startup after sitting overnight.

You can pull the boost hoses and look for excessive oil pooling. Clean it out and see if your problem is alleviated. Also, inspect your PCV hoses and check valves.

Usually when a turbo goes, the psi out put drops (as mentioned... boost gauge) and the car doesn't just puff smoke, it crop dusts the land behind you (LOTS of smoke).

How many miles and has the turbo or engine ever been replaced or rebuilt?

 

its worth noting that its not good to run on a blown turbo very long. and if its a turbo seal on the hot side of it, you wouldnt have oil in the intake. you mentioned compression is good. what were the numbers on each cyl?

 

so if i only burn oil when there is vacuum and not when there is boost, compression is fine and stem seals have been replaced, then its definately the turbo? I am producing a cloud of blue between lights, and a fog of white/light blue when I let it sit for 7min after its warmed up. boost level also tends to fluctuate if im at half throttle.
kinda new to this so I apologize.

 

Pm me as Im not on the a4 forums. But there are two types of compression test you should run. One being a wet and the other a dry comp. test. The dry one is the one most ppl are familar with. The wet comp. test works on the same principle but before screwing in the guage to the cylinder drip about 1 tlb spoon of oil into the cylinder. This wil act as seal for the rings. As you crank the engine, comp. readings will be a bit higher but if you notice a drop in pressure as your cranking you have ring failure.

 

Wet compression tests are often inaccurate. If it passes a normal compression test, there is no reason to do a wet test. A wet compression test is to determine if the rings are the cause of the loss of compression if there IS a loss of compression noted during the regular compression test. A leak-down test is much more accurate and can determine if it's rings, valves, or sometimes even a cracked head or bad head gasket. He said compression is fine, so he should be looking elsewhere.

Adrenaline, unfortunately, from the info you've given, it sounds like a bad turbo.