ivancolesnic

alright guys...coming full circle with my 2001 A4, 1.8TQ. It had a smoking issue when I bought it, here are the things I fixed so far: new headgasket and rebuilt head, new turbo, new valve cover breather hose (the Y hose that attaches to the valve cover - it was utterly destroyed, makes me think there is something wrong with the PCV system). I originally thought it was the turbo for sure, since the exhaust side turbine was just laying in the housing (not attached to anything) when I pulled it off.

The car just blows billows of smoke. I replaced one vacuum check valve (the one over the air filter), fixed a little smoking in the engine bay, found another blown check valve (under the intake manifold) didn't have one to replace it with, but I got it to seal for a moment. I don't know what else to focus on. I think my smoking is most likely from some vacuum leak or high crankcase pressure. The way the Y shaped hose was destroyed made it seem like high pressure could have caused it...I did replace the EGR valve with a used newer one, not sure if that affects the system much? Also, the fact that both of the check valves were blown at the seams hints toward high pressure and the fact that they were both blown is also odd. Usually I have only had one blow. The previous owner did use conventional oil and cheap-*** oil filters. Could sludge have clogged up some vacuum lines?

Thanks in advance for any help,
Ivan

auditechstef

hello ivan.
how bad is the smoke mate and how meny kms or miles on the clock.?

now im only sugesting here.is the turbo oil seals ok .have you checked the plugs are thay black and sooted .also im thinking it might be the oil rings.now for the crank case.it should never be pressurised other wise it will starve the engine of oil.let me know what you find out

Bobby Kinstle

It's pretty common for the Y pipe (suction pump) to clog up after all these years. You probably didn't do anything wrong to it, it just happens. Any time people repair oil leaks, they should also replace the suction pump as that's often the cause of the oil leaks in the first place.

As for as the smoke goes, I've seen that happen when the oil seals in the turbo go bad. This usually happens when you are heavy on the throttle but not as idle.