This is the story:
I got my 1997 A4 1.8T with 95,000 about a year ago. I had been told by previous owner that timing belt was replaced around 70K. Well, at 110,000 the tensioner failed and ... $2,500 later the car got its groove back :-). I still wonder what I could have done with that "lost" money. As I later found out, The timing belt was replaced but the tensioner had not been updated, and that's why it probably failed.
After the valve job and couple trips back to the mechanic (various oil leaks, valve cover gasket replaced twice) the car was running fine without any oil leaks.
Then, after I put maybe 1,500 miles it seemed like car is not boosting 100% and then it lost the boost completely. It seemed like turbo wanted to spool but only it would make the griding noise.
So, I got a used KO3 (I could not afford a new one or an upgrade since I just put almost $3,000 in valve job) from a guy on the internet who told me the turbo only had 36,000. When it arrived it seemed to be fine (no shaft play) or visual blemishes so after couple of hours the replacement was in. I replaced the oil (mobil1 synthetic which was always used) and made sure that everything was assembled properly. The car drove just fine with the new/used turbo. Everything was nice until maybe 1,000 miles later. The car, again, was noticeably not able to boost 100% and on my way home after taking off from the lights (1 and 2 gear, reving to maybe 4,500 rpms) started to make the same griding noise as with first failure and lost boost completely.
Now, with the second turbo failure I have no idea what is going on. I would appreciate any input from anybody who expierenced something similar or maybe is just more knowledgeable with 1.8T engines.
Is there anyway of testing feed lines (oil/coolant)or operation of intercooler in your garage before installing another turbo. What should I do?
Thank You for your help.

 

Almost the same thing happened to me--only my second turbo failed within 24 hours of installing it. Turns out that the oil-feed line was clogged. I removed mine and tried to blow some air through it using a compressor and nothing would go through. I cleaned it out as a temporary fix but ultimatley replaced it with the third turbo.

 

2nd, Oil line is probably clogged.

 

Although you seem like a knowledgeable person, just incase you didn't know, its always a good idea to idle the car after driving to allow the turbo to cool down. IIRC the 97's heat shielding isn't all that great and makes them more prone to these failures. I haven't experienced it but thats what I've been told.

 

I was probably leaning towards lack of proper lubrication. I will definitely check/clean the oil supply line after I dismount this turbo. Any suggestions where could I get a good deal on used turbo or should I let some place rebuild it? Man, it seems like another couple hundred bucks is down the drain again...
Oh, by the way, does anybody have a Garrett gt28rs turbo kit by atpturbo.com running on a A4?

 

I can give you one, you'll need to pay shipping and use your original waste gate

 

I greatly appreciate it. How do you want me to pay for Shipping in most convenient way for you...paypal? I just sent an e-mail.

 

By the way, No problem with the wastegate...I have two of them now laying around :-)

 

you do know you should be warming-up and cooling-down a turbo, right?