ColdFeet

iTrader: (4)

Tried searching different phrases with lots of results, none useful. I know I have seen previous postings - but can't seem to find them now.

I am the un-proud owner of a very, very metallic sounding squeal. Sounds like a bearing going out with a wobbling metallic squeal. I'm suspecting and it seems to be coming from the primary turbo and as it spins up or slows there is a speed range where things are hitting. Manually blipping the throttle into 4K or so range will repeat it pretty much each time. Then again, almost everything that I think I know going into a problem on this car has been proven wrong. Oh, I so want that to happen again....

No unusual oil consumption. No noticeable changes in boost patterns or performance.

So, those that I have non-catastrophic turbo failures - what were the symptoms and can anyone point to the thread(s) with captured audio?

Thanks.

ColdFeet

iTrader: (4)

Edited to attempt clarity and basic grammar

alexdimen

iTrader: (13)

There is no such thing as a non-catastrophic turbo failure that involves noise. At the very least it woould need to be broken down, balanced, and rebuilt with a new compressor wheel, turbine, or both.

I wouldn't drive the car at all. If that noise is coming from the compressor rubbing the housing, it's sending aluminum scraps into the engine.

I once failed to loctite a compressor nut and the wheel came off and I had similar symptoms. After rebuilding the turbos, my compression gradually degraded until I needed an engine rebuild. This was due to scoring on the rotor housings, which ate up the seals.

ColdFeet

iTrader: (4)

Perhaps poor wording on my part. My point was blades have not gone through the engine (yet), and there is no pooling of oil. Other than the noise, I have no other obvious symptoms that I would associate with a failing turbo.

Are you saying that turbos don't make noise as they begin to fail, or the narrow rpm range would tend to exclude turbo failure??

Sigh... There's was a mental image I could have done without.

So when you say 'compressor', I should be able to pull the downpipe and examine for damage or excessive play?


Now I am confused - not to worry, it's my natural state. So you have observed these symptoms and it was the turbo regardless of reason?

Pulling the turbos is a big job for me and I really want to diagnose this as far as I can prior to taking such a major step. Any alternative theories would really be welcome.

Again - I thought I've seen thread(s) with audio of a turbo going out. Was .... well, far enough back I don't recall the time period. Ring a bell for anyone? I know that sounds may differ or even be similar for different problems. I'm just trying to think of an alternate possibility that I could research


Thanks for replying!

Scott

alexdimen

iTrader: (13)

It doesn't matter if blades have gone through or not. If a compressor wheel is rubbing, then there is metal being abraded from the wheel and housing.

Your turbo is screeching, yet somehow you KNOW that you haven't lost pieces of it down the exhaust or intake... without removing anything?

No. The compressor is on the cold side. You need to remove the air box and primary turbo intake elbow to view the compressor.

I'm saying that I've had a turbo fail due to builder mistake (myself) and the results were not pretty.

Seeing is believing. You can't click and clack your way to a diagnosis. It's pretty easy to pull off the turbo inlets and check out the compressors.

ColdFeet

iTrader: (4)

Thanks. Spelunking I will go.
Noise seems to be coming from secondary turbo (firewall side) but could be getting faked out. I'll examine both.

ColdFeet

iTrader: (4)

Primary compressor blades have a faint discoloration on most of the the leading edge, secondary compressor looks pristine.. No chips, gaps, or ragged edges.

Sidewalls look excellent - just ever so cleaner where the blades sweep. No visible streaking or scoring.

Going to try capture some audio to post and try again to get a better feel from where the sound is coming from.