How to evaluate turbocharger condition

[relative4]

Starting a boost leak test on the '02 A4 1.8Tq I just picked up. I did find a little leak in the connections behind the intake manifold at 6 PSI, but I had trouble getting there because even at 1 PSI, air is glug-glugging out through the oil at a pretty high rate. Doesn't say good things for the oil seals in the turbo. for what it's worth, I'm not getting an underboost code or anything like that. How best to go about figuring out how bad this snail is? Thanks!

[chad99]

You can use soapy water in a spray bottle to help with finding leaks.
The glug oil noise is normal, also I remove the oil cap for testing.

[123lilc]

I have the same problem but how am i supposed to test when it wont even hold air it just glug glug glugs and loses all air almost instantly?

[chad99]

Hopefully you're using an air compressor so it should not be a problem running out of pressure, the leak test will always glug glug the oil, it's not an instant loss of pressure

[diagnosticator]

I have the same problem but how am i supposed to test when it wont even hold air it just glug glug glugs and loses all air almost instantly?

The flow path connection from the charge air system to the crankcase below the oil level in the pan must be disconnected and plugged for the leak check. Remove the oil fill cap also, to prevent over pressurizing the crankcase and blowing out the crank and cam seals

[diagnosticator]

Starting a boost leak test on the '02 A4 1.8Tq I just picked up. I did find a little leak in the connections behind the intake manifold at 6 PSI, but I had trouble getting there because even at 1 PSI, air is glug-glugging out through the oil at a pretty high rate. Doesn't say good things for the oil seals in the turbo. for what it's worth, I'm not getting an underboost code or anything like that. How best to go about figuring out how bad this snail is? Thanks!

A rough estimate of wear in the turbo shaft bushings in a K-03/04 can be checked by moving the compressor impeller sideways and note the amount of play in the shaft bushings. A new turbo will have about 0.25mm total side play max. This will not reveal anything about the condition of the shaft seals as being coked up or clean. If the piston ring type seal ring becomes fouled with carbon, it won't be able to move around with the turbo shaft, and will leak a lot of oil into the compressor or turbine housing. (almost always the turbine end shaft seal due to the high heat.) The shaft seal rings can only be checked by disassembling the turbo. Snail? This is slang for the turbine housing or the compressor housing. There is no leak checking either housing as the housings are not involved with the shaft seals. For the turbine housing, check for cracks.

[relative4]

The flow path connection from the charge air system to the crankcase below the oil level in the pan must be disconnected and plugged for the leak check. Remove the oil fill cap also, to prevent over pressurizing the crankcase and blowing out the crank and cam seals

Thanks, I'm not sure which connection you mean. I disconnected and plugged the pancake valve to the PCV valve and removed the oil fill cap, but if I understand the flow path from the charge air system to the crankcase below the oil level, that has to be the turbo's oil return line, correct? So are you saying to disconnect the oil return line from the turbo?