Turbo screech when boosting *youtube vid inside*

Hey everyone, I am back with a new problem! It all started yesterday when I was accelerating on an onramp to the interstate. That particular on ramp has a slight incline, and is rather short, so to get on the freeway there requires every bit of power from my little 1.9.

So there I was in 3rd gear, full throttle, trying to merge, when I hear sort of a screeching/howling noise. I honestly thought it was the dump truck that was next to me, so I shrugged it off and continued on my merry way.

Now, every time I hit roughly 1800 rpm to 2400 rpm, the screech returns. If I rev it in neutral, the screech comes back after 3k rpm. Its loud enough to be heard over the radio.

When I got home, I let it cool, and then tore into it. I removed both rubber hoses going to the turbo, and out of curiosity, I wiggled the turbo shaft (it wiggled just barely enough to notice). I checked out all the threads I could find on the subject and went through some diagnostic procedures. I pulled apart the egr hoses and checked all connections, as well as the metal hose that comes off the egr. All connections were good, all gaskets in place, and bolts are as tight as they should be.

I even checked the bolts on the egr cooler as well as the intake, and all were tight. I put everything back together, nice and tight, double checking my work. I test drove the car, and the screeching came back as strong as ever. I am baffled. I do not have $800 to replace the turbo (if that is the case)!

The car still runs fantastic, as far as I can tell the turbo still boosts (although I haven't pushed it because I don't want to blow it up) and after cleaning the intercooler last week, there was still no oil in there. I checked the oil on the dipstick and it still read 'full'.

Does anybody have an idea of what kind of repair I am looking at?

Heres a youtube video of what is going on. https://www.youtube.com/watch?v=C8N5sruBO1w&feature=youtu.be

You are fairly certain there are no boost leaks? Did the turbo shaft slide in/out at all?

Your turbo could be out of balance, turbo shaft damage, etc.

I would remove the intake pipe from the turbo again and check for in/out shaft play. If so,your turbo needs replaced. You could be hearing the internals of the turbo moving on the shaft and hitting the exterior housing of the turbo.

Let us know what you end up finding out and how you repaired it.

I went over all pipes/connections to make sure there were no boost leaks, although it is very possible that one of the connections isn't sealing as well as it should.

I did check for in and out play, and there was barely any (when it was kind of warm still). I checked this morning and there was just barely enough to make it 'click' if I pushed/pulled hard enough. Same with the up/down/side to side play. It spun easily as well, no roughness/grinding feeling unless I pushed down really hard while trying to spin, and even then it was a 'resistance' not a 'grinding'. No blades touched the housing.

Anything is possible at this point though, I will pull the pipes off again and double check. If possible, I will make a video of the turbo play later today or tomorrow.

If the turbo is bad, would I have had any weird noises beforehand? I did find oil in the intercooler (about 1/2 cup) a week ago, maybe that was all the warning I had?

When your bearings are worn enough to get excessive oil consumption, you'll get smoke and a possible runaway. Most turbos allow some oil into the IC circuit-that's normal.You really need to get it on VCDS and log your requested versus actual boost. Keep your foot out of it in the meantime and keep looking for leaks.

Did you check your down pipe? Video turbo sounds like when down pipe is disconnected. Just a shoot in the dark.

I do get a little bit of white smoke when I first start the car in the morning, but otherwise it is smoke free even under full throttle.

So far the only symptom of problems is the noise. The turbo sounds completely normal up until I request boost. I'm hoping I just have a bad hose connection.

Also if it helps, I'm at 283k miles and its the original turbo (as far as I know)

dweisel said:

Did you check your down pipe? Video turbo sounds like when down pipe is disconnected. Just a shoot in the dark.

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Interesting, no I never checked it. I'll look at it right now

Edit: Downpipe is connected

One thing maybe you could try would be to remove one of the pipes on the boost side so it makes NO boost, that way if it was a boost leak, it would go away? But that would also put less load on the turbo and less load on the bearings.

If it makes the noise just revving in your driveway, you could do this, or I suppose drive it shortly, might go into limp mode though because of the no boost.

That might say its turbo/downpipe vs leak on the boost side.

duwem said:

One thing maybe you could try would be to remove one of the pipes on the boost side so it makes NO boost, that way if it was a boost leak, it would go away? But that would also put less load on the turbo and less load on the bearings.

If it makes the noise just revving in your driveway, you could do this, or I suppose drive it shortly, might go into limp mode though because of the no boost.

That might say its turbo/downpipe vs leak on the boost side.

Click to expand...

I did disconnect one of the boost pipes and the noise went away. Also, I unplugged a vacuum line from the turbo actuator just out of curiosity and the noise went away then too.

After plugging in the boost hose again, I took it for a drive and the noise was softer, and also turned into more of a high pitch squeak (almost like if you make a balloon squeak by pulling on the tongue as you let air out). That tells me it's probably a boost leak at one of the connections on the boost pipe, most likely where I recently had to replace a clip where the two parts of the boost hose connect.

I made that repair a week and a half ago and it's been fine (250 miles since repair) assumingly up until now. Does that sound like it could still be a likely culprit?

Everyone's help is GREATLY appreciated

When my 2004 sounded like that, it was the cracked EGR pipe causing it. New EGR pipe with all three bolts, +10k miles and the sound hasn't come back. I found someone else's youtube video that took me to that diagnosis. I know the ALH plumbing is different, but that's definitely what a boost leak sounds like, especially in that RPM range.

where2 said:

When my 2004 sounded like that, it was the cracked EGR pipe causing it. New EGR pipe with all three bolts, +10k miles and the sound hasn't come back. I found someone else's youtube video that took me to that diagnosis. I know the ALH plumbing is different, but that's definitely what a boost leak sounds like, especially in that RPM range.

Click to expand...

I thoroughly checked the egr pipe and it seems good. Its still shiny (no soot on outside, indicative of a crack) and it is tightly secured (all bolts). Could you see the crack on your egr pipe when you took it off? Also, did the sound slowly come on, or did it come on suddenly?

Sounds like an air leak, not a failing turbo.

I have the same noise - been too snowy here to investigate. Planning on checking my pipes and gaskets around the turbo and intake/exhaust manifolds now that it's warming up. Mine only happens when I hit the upper range of bost. Stops immediately after I let off the pedal.

I agree with VeeDubTDi, sounds like an air leak.

Well, I found out what is going on. Turns out it was definitely a boost leak. One of the pulleys next to the upper intercooler hose wore a good sized hole into the hose. Looks like it happened to the P.O., because I found black duct tape covering the hole (the tape had a hole blown through it). Guess I'll just keep putting duct tape on it for now (seems to be holding very well, no more noise or leaks). Obviously I don't expect the tape to hold forever, but it will hold me over until I can pay $119 for a replacement

I'm just happy to drive it again

Also, some pics of my issue..

Glad to hear it's not a turbo issue! Good find.

You can replace that pipe with some aluminium and silicon for much less money.

andrewspearns said:

You can replace that pipe with some aluminium and silicon for much less money.

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Never thought of that. Thanks for the idea!

That's a pretty gnarly gash! Glad you got to the bottom of it.

andrewspearns said:

http://forums.tdiclub.com/showthread.php?t=343394

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Awesome, thanks for linking that for me.

An update, 300 miles later and the duct tape is holding great! Should be able to get parts ordered soon.

You could probably find a used one in the classifed section of the tdiclub or on ebay.