B5 AJL turbo no good :( HELP!!

[Pat D]

My B5 turbo has been low on boost, lately and there are small powdery bits of what looks like aluminum in the intake pipes mixed with the oil. I'm guessing this is bits of compressor wheel. I used a mirror to inspect the wheel, and doesn't look too bad but it has been rubbing and doesn't spin freely when very slight pressure is pushed against it. There is some back and forth play, not heaps but it is there.

I plan on getting another motor put in later in the future if it has sucked some crap in, but I think the oil and dodgy front mount cooler (previous owner install) may have stopped most of it.

Bottom line is, I need to get back on the road asap and have no idea what turbo it is. There are heaps of ebay jobbies available that say are good for B5 A4's, but are they all the same?

[Pat D]

So an update on this.

I bought a reco'd turbo, brand new oil pump, gaskets, fluids and fitted everything back togther meticulously. Flushed the turbo oil feed pipe, primed it with oil, and cleaned out the whole intake tract including the intercooler. Finished it all in about 3 days and fired up... Still the same problem, no boost, and sucking fuel like a truck.

Plugged in the laptop, no fault codes. Re-configured the wastgate hoses so that it would be forced shut, still nothing. Checked and checked and checked and checked.

I ended up pulling the catalyst out and found the rear part of the internals had collapsed and blocked the exhaust, causing too much back pressure and not allowing the turbo to spin. Did what anyone else would do and fitted a "new" catalyst.

Needless to say, it now runs better than it ever did. Even the bellow clamps required a re-tension after blowing them off the intercooler.

The fines in the bellows which I thought were compressor wheel dust were actually particles of the catalyst that have managed to come back through the head and past the throttle.

Hopefully this helps anyone else out with low boost sypmtoms

[simon20vq]

Glad you sorted and thanks for the conclusion always good to know what the problem was!