Turbocharger Failure: Signs and What to Do

Hello everyone, have a great day. I'm new here and came across this website through a recommendation.

'Regarding my problem: For a few weeks now, my turbocharger has been making an indefinable noise in the range of 1700 to 2300 rpm, specifically during the pressure build-up phase, but it then becomes quieter again. I've tried searching for similar posts on this forum, but haven't found anything, so I'm trying to describe this noise. It is NOT the typical turbo whistle or howl; it's more of a quiet rattling or grinding sound, which could also be described as a 'chirping.' The oil consumption is normal, and I can't detect any noticeable loss of power. I've also examined the area around the turbocharger, and all the hoses appear to be intact and in good condition; I haven't found any oil leaks either. At Audi, they told me not to worry about the noise as long as the turbo is producing its pressure, it's not defective. There were also no entries in the error memory.'

I just want to be careful and avoid any further damage, so I'm looking for advice here. Could it be that a bearing is damaged and the impeller is rubbing somewhere? Or could it also be vibrations from an air column? I haven't had time to check the axial play myself yet. Maybe someone here recognizes this noise and can explain where it's coming from, or whether I should have the charger checked more thoroughly...

The car has 110,000 kilometers on the odometer, but it's well-maintained with a complete service history, including all inspections and a new timing belt.

Thank you in advance, best regards.

stephan.

Hello,

Unfortunately, you didn't include the engine code letter.
Have you ever experienced problems with a difficult VTG adjustment? There are cases where the impeller vanes were stuck. Forcibly releasing them (usually done in workshops) could cause a significant amount of debris to detach and damage the turbocharger.

The identification letter is AHU, and it's located at the bottom of the signature...

No, my loader doesn't have a VTG adjustment, but even if it did, it wouldn't make such a chirping noise.

Oh, I forgot to mention that my EGR valve is supposedly 'defective,' but I doubt that's actually the problem. Another mechanic told me something about air turbulence. I really don't know what to believe anymore...

Best regards, Stehan.

Sorry.

Okay, I understand. Please provide the German text you would like me to translate into English. I will only provide the translation.

Is there anything leaking behind the loader?

as described here:
I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.
Please provide the German text you would like me to translate into English. I need the text to be able to help you.

'That's the strange thing, everything seems sealed. All the connections are dry and the clamps are tight. If it were a crack in the hose or a leaky connection, the whistling sound wouldn't just be in that specific RPM range, but constantly, I think... No, it really doesn't sound like escaping air; it definitely seems to be coming from the turbocharger itself. What about this famous solenoid valve? Could that be the cause? Does that thing make noise when it operates?'

Is something loose somewhere? It also makes a chirping sound at certain RPM ranges.

Best regards, Rainer.

hello rainer,

'No, I hadn't thought about a screw yet... Are you talking about directly on the turbo itself? When I look underneath, I only see a metal casing from which a red fabric hose runs somewhere. The casing itself is quite dirty and dusty, but there's no oil leaking from it, and the hose itself looks a bit pale, although it's also completely dry. Well, I'll have a look around the turbocharger area tomorrow and will post the results here on Monday. But what about my suspicion of excessive axial play? Could that really be so large that the impeller blades are scraping against the housing? I once read somewhere that the play stabilizes with increasing turbo speed, which would explain why the noise gets quieter above 2300 rpm... I can see that I'm probably going to have to get my hands dirty and take a closer look at the turbocharger. A certain amount of play is supposed to be normal, but could a turbocharger already be so worn out with regular maintenance intervals? After all, this car has just been broken in at this mileage...'

Hello.

I meant loose metallic parts that can rattle against each other.
Identify the source of the noise and check everything in the surrounding area for any obstructions or things that might be stuck.

Best regards, Rainer.

Okay, I will do that, thank you very much .

Hi Stephan,