TTRS - Strange sound when cold over 2k RPM?

[- Jeremy -]

For you TTRS guys in the northern climates: Does your car make a funky sound when cold over 2,000 RPM? Mine is pretty consistent. When the car is cold or semi-cold, and I start to rev it over 2k, a strange rattling/vibrating/hissing/grinding sound eminates from the engine bay. At first, I thought it was maybe a blow off valve preventing boost when it's so cold. But it just sounds awful, so I don't think that's it. After the car warms up for a few minutes, it's fine. So I just short-shift at 2k until it warms up. The car runs like a champ otherwise. No CEL, etc. It could be a cold heat shield that needs to warm up? I don't know.

The car exhibits no other problems, so I'll wait until my first inspection to have it looked at. Just curious if anyone else hears something similar from theirs. I need a friend to help out while I try to pinpoint the problem.

- Jeremy -

[Black BeauTTy]

There's been a lot of chatter about this on QW...http://forums.quattroworld.com/tt2/msgs/17368.phtml

I don't think anyone has figured out what it is though.

[LongviewTx]

I've noted it on cold mornings, after allowing RPM to drop to 750 then driving off slow, second gear. Disappears after driving onto and at roadway speeds. I have only heard it initially and when the engine temperature is still not to center of gauge.

I have assumed it is part of that sophisticated german engineering, doing what it is supposed to do at these non-normal operating temperatures.

[- Jeremy -]

There's been a lot of chatter about this on QW...http://forums.quattroworld.com/tt2/msgs/17368.phtml

I don't think anyone has figured out what it is though.

Sweet Baby Jesus, I hate the layout of that forum.

Otherwise, it sounds like they're probably hearing what I'm hearing. Although mine is only RPM related and has nothing to do with the clutch or brakes. Although, I suppose it seems amplified when I hit the clutch above 2k. Presumably because the flywheel can spin faster for a second when disengaged.

- Jeremy -

[neonova6]

Hot damn, I started hearing this just this last weekend. A short trip to get my hair cut Saturday morning, and I noticed, what sounded like the synchromesh not "meshing" from under the hood ( disclaimer: note, NOT implying I think it's the synchromesh, that's just what I think it sounds like). By the time I got a few blocks down the street it was gone. I've heard it again the next morning and went away after a few minutes. Then this morning, no noise. So I'm not really sure what's the correlation other than it 'sometimes' happens when driving and the engine is cold. When it does occur, the clutch is engaged, and engine is in gear. The noise goes away when I take it out of gear.

I should note, these were not cold mornings by comparison, single digit positive centigrade overnight.

EDIT: Noise happened again this morning. I was originally mistaken thinking it only happened while in gear. Rev the engine over 2k while in neutral and no motion, and I hear the noise.

[lcrcr]

I commented on the QW forum that my TTS makes a similar sound. And so does my Golf R. I think it is the Haldex trying to deal with cold hydraulic fluid. (Of course, I could be full of fluid myself.)

[- Jeremy -]

I commented on the QW forum that my TTS makes a similar sound. And so does my Golf R. I think it is the Haldex trying to deal with cold hydraulic fluid. (Of course, I could be full of fluid myself.)

Okay. That's super interesting. But it makes me feel better that it's not only the TTRS that does it. I guess I won't worry about it, but it's a little embarrasing when driving away from the office and everyone hears that godawful noise.

I still wonder what it is, though...

- Jeremy -

[joshsmith]

Yea mine friggin does this!! Thought it was a lose fan belt or something... Only happens when cold start though and once warm/ after 5-10 min all is well. Go figure


Sent from my iPhone using Tapatalk

[YYC Dubber]

Okay. That's super interesting. But it makes me feel better that it's not only the TTRS that does it. I guess I won't worry about it, but it's a little embarrasing when driving away from the office and everyone hears that godawful noise.

I still wonder what it is, though...

- Jeremy -

hmmmm.... that haldex idea sounds rather reasonable... I drive my (fwd only) GTI in cold temps (-10 all the way to -30*C) and I have never experienced any such noise...

[- Jeremy -]

hmmmm.... that haldex idea sounds rather reasonable... I drive my (fwd only) GTI in cold temps (-10 all the way to -30*C) and I have never experienced any such noise...

But my R32, using the previous generation Haldex, did not do this.

I know the Golf R is using the latest generation Haldex like the TTRS. But does the TTS?

- Jeremy -

[lcrcr]

But my R32, using the previous generation Haldex, did not do this.

I know the Golf R is using the latest generation Haldex like the TTRS. But does the TTS?

- Jeremy -

yes. The TTS (2011 anyway) is the same as the R.

[DrDomm]

I mentioned this months ago in the "Quirks" thread. Got no response. Guess it gets cold here sooner.

[fourtunes]

This is very interesting, I was wondering if I was the only one suffering through this problem (and if I had managed to damage my car in some way). It's good to hear that I'm not.

I picked up my TT-RS at the end of December and didn't notice the noise for the first week or two. Since then, I'd like to say it has been getting progressively worse, but I cannot be sure. I went easy on the engine for the first ~1200 miles and often let the car idle for several minutes before taking off. In any case, the problem is bad enough that I've already taken the TT-RS to the dealer twice.

The first time around, I described the symptoms as clearly audible metallic grinding sounds when spinning the engine up to ~2200 RPM. As far as I knew, this would only happen if the car had sat for several hours, and I always let the engine idle long enough for the RPMs to drop below 1000 before attempting a reproduction. I also advised the dealer that as the engine warmed up, the problem would move up in the rev-range and become less pronounced before disappearing completely at ~3000 RPM. Lastly, I mentioned that on some days, the car was perfectly fine.

Since the S5 I owned prior to the TT-RS was a bit of a problem child (steering vibration, carbon build-up, ...) and thus a somewhat regular visitor at the dealership I had it serviced at, I have a good working relationship with my service adviser there. Because of that and because the car is brand new, the dealer took my concern seriously and kept the car for a few days while attempting to diagnose the failure. Their first guess was that the noise was coming from the transmission. They also escalated the problem to Audi, who sent an area rep to investigate. Unfortunately, the TT-RS decided to behave on that day, yielding little useful data.

The (mostly disappointing) result of the first visit was that heat shielding was adjusted speculatively. The Audi rep said to bring the problem up again at the 5000 mile service, unless it went away by itself. It was suggested that unless matching reports from other TT-RS owners came in, Audi would be unlikely to investigate proactively.

Two weeks later, I took the car back to the dealership and made it clear that I was very concerned that the problem might be serious, and that I did not think it was acceptable for a brand new car to exhibit such (embarrassing) symptoms in the first place. I had also determined that it was generally sufficient to let the car sit for 2-3 hours in between reproduction attempts, and that if the engine wasn't given time to idle initially, the sounds were often audible at much lower RPMs than ~2200 early on.

The dealer investigated again and apparently had more luck reproducing the problem at its worst, as my adviser informed me that they'd captured audio/video coverage and forwarded it to Audi. He also said that he was able to make the problem happen most consistently by spinning the engine up to ~2000 RPMs and then releasing the gas pedal completely, allowing the engine to sweep the rev-range quickly on the way down to idle.

Long story short, the Audi rep came out again but still couldn't pinpoint the source of the noise. He did however notice vibration on some rod in the intake manifold assembly that apparently wasn't there on another TT-RS he had looked at. To eliminate it as the culprit, a replacement part was ordered. Unfortunately, there's little in the way of parts available in the U.S., so the part was ordered from Germany (with a 10 business day lead time). Since the dealer was also missing a single-use gasket and couldn't put the engine back together, my TT-RS has been sitting at the dealership since.

This was two weeks ago, so chances are I'll learn more this week.

[mtbscoTT]

Weird. Granted it doesn't stay cold here in Texas for long, my RS has been started and run in 30-40 degree weather some since I got it in August and I haven't heard any strange noises at all.
When I first start it up in the morning, or after it's been sitting a few hours outside, I get the fast idle. I don't touch the gas and let it cycle back down to regular idle which usually takes a minute or so and then I drive on easily. I put the onscreen display to oil temperature and do not rev over 3K until it starts showing the oil is warming (starts showing at 140 degrees).
Don't know if my start/warmup procedure is more conservative than some of yours, but sounds like your cars are making the noise right from startup, hope it gets resolved or at least diagnosed accurately.

[fourtunes]

I've practically always waited for the idle to settle (which typically takes 1-2 minutes) and then let it idle a bit longer (at least long enough that when I finally press the sport button, the exhaust flap opens right away) before setting out. I've also avoided pushing the engine until the oil temperature has exceeded 90°C, so I'd say I've been leaning on the conservative side. But none of this seems to make a difference as far as this problem is concerned. Unless I let the engine idle for close to 10 minutes, it will emit the rattling sound most of the time.

[fourtunes]

Oh, and since I'm located in the Bay Area, intense cold isn't really a factor.

[- Jeremy -]

Yep. What you guys are saying is exactly the same as I'm experiencing. Even down to the startup/warmup procedures. I always let it settle down into low idle before driving off. And I never take it above 3k until it's reading 90C, etc.

I think we can rule out the Haldex unit as the culprit because the problem is directly related to RPM and not to road speed. I do have a feeling that it's a problem with a shield or a shaft of some sort. Once the metal heats up and expands, the problem goes away.

Well the good news is that enough of us have the problem. Now we just need to plan a mass registration of complaints at our 5k services.

- Jeremy -

[neonova6]

Oh, and since I'm located in the Bay Area, intense cold isn't really a factor.

Which dealer did you take yours to? I've not take mine in yet, so it would be nice to go to a service department that's already familiar with the problem.

[fourtunes]

Which dealer did you take yours to? I've not take mine in yet, so it would be nice to go to a service department that's already familiar with the problem.

Audi Stevens Creek

[fourtunes]

I heard back from the dealer today. They replaced the part and put the intake manifold back on, but the noise persisted. The Audi rep came out again and the new theory now is that it's a problem with the turbo. More specifically, the speculation is that the wastegate isn't operating correctly. They're continuing their investigation.

[DrDomm]

I heard back from the dealer today. They replaced the part and put the intake manifold back on, but the noise persisted. The Audi rep came out again and the new theory now is that it's a problem with the turbo. More specifically, the speculation is that the wastegate isn't operating correctly. They're continuing their investigation.

Well, this would be a common problem, then.

[neonova6]

Well that's a disappointment, though it's not like it was not expected. At least they have a second theory to go on... I was thinking on they way home today, that it might be turbo related. Almost as if there wasn't getting enough oil into the bearing. Letting it sit long enough gave the oil enough time to drain back out of the bearing... But I'm just grasping at straws here. I do know, that even when the engine has been running, and the oil temp is at the nominal 100*c, I can still get the noise to occur every so often when the engine RPM is dropping back to idle. I'm going to make a video this weekend and send it Audi. This issue is really starting to bug.

Thanks for the update!

I heard back from the dealer today. They replaced the part and put the intake manifold back on, but the noise persisted. The Audi rep came out again and the new theory now is that it's a problem with the turbo. More specifically, the speculation is that the wastegate isn't operating correctly. They're continuing their investigation.

[- Jeremy -]

As I mentioned in my first post to start the thread, my first suspicion is that it was the wastegate/BOV. It sounds like excess pressure is being vented to me. Albeit without the cool Fast & Furious effect going on. But I thought that the modern VAG engines were recirculating excess boost internally and not venting to atmosphere in order to speed up spooling times. Is this not the case anymore? I remember there being big problems with faulty N75 units on the 2.0T. My TTRS repair manual shows a N75 Wastegate Bypass Regulator Valve and a N249 Turbocharger Recirculating Valve. The problem may lie with the N75 or the wastegate itself?

Are the TTS and Golf R using the same wastegate? I'm sure they're all using the N75. VAG has used them for years and they always seem to fail. A good way to tell is to log boost pressure with VCDS. But the TTRS has the digital boost guage. But I wonder how accurate it is?

- Jeremy -

[Marty]

Mine does this too.

Audi Stevens Creek

There were a total of 3 TT-RS cars at Stevend Creek Audi when I went there earlier this week for service (one black, one Suzuka, one Daytona). Was yours the Daytona parked in the back?

[JohnLZ7W]

It's an odd sound because it's related to engine speed but it does occur at the same frequency of the engine speed.

For me it usually occurs around 3k rpm when the engine is very cold, like first thing in the morning. When it occurs it's a very fast rattle that doesn't really change frequency at all, at some point as the engine speed drops off it just stops.

This is also with very light throttle and the boost gauge hasn't moved at all, basically I'm not giving enough throttle to generate any boost at this point. That doesn't mean that the turbo isn't spinning but I don't think the rattle is related to the compressor/turbine wheel because that would change in tone as it wound down. It could be something with a sticky wastegate I guess.

And yes, the TTRS does use a recirculating valve. If you look you can see a ~1" sized hose run from the silver elbow below the throttle body back over to the intake just past the airbox, into a coupler that looks like a MAF housing.

I haven't poked around enough yet to locate the actual N75 but I imagine there is one somewhere.

[neonova6]

Three others!? Any idea what they were in for? That's not very assuring.

Mine does this too.

There were a total of 3 TT-RS care at Stevend Creek Audi when I went there earlier this week for service (one black, one Suzuka, one Daytona). Was yours the Daytona parked in the back?

[fourtunes]

Mine does this too.

There were a total of 3 TT-RS care at Stevend Creek Audi when I went there earlier this week for service (one black, one Suzuka, one Daytona). Was yours the Daytona parked in the back?

Yes, the Daytona Gray one probably is mine.

[Marty]

Three others!? Any idea what they were in for? That's not very assuring.

Mine was there to get the front brakes replaced due to squealing. They still can't figure out the pedal vibration issue. The Daytona one was fourtunes car. Not sure why the black one was there...

[fourtunes]

I heard back from the dealer today. They replaced the part and put the intake manifold back on, but the noise persisted. The Audi rep came out again and the new theory now is that it's a problem with the turbo. More specifically, the speculation is that the wastegate isn't operating correctly. They're continuing their investigation.

I called my service adviser this morning for an update. Apparently, a replacement turbo was ordered and arrived at the dealership yesterday. It will likely be installed today and the car checked again for the noise.

If I'm lucky and the noise is gone, I may get the car back tomorrow or sometime early next week. Else the odyssey will continue. I have to admit that I'm tiring of Audi antics and beginning to think more seriously about replacing the TT-RS with a car that works. I've owned the TT-RS for about three months now, and between two visits, it's now been at the dealership for close to one of those months. It's continuing right where the S5 left off...

[Marty]

I called my service adviser this morning for an update. Apparently, a replacement turbo was ordered and arrived at the dealership yesterday. It will likely be installed today and the car checked again for the noise.

If I'm lucky and the noise is gone, I may get the car back tomorrow or sometime early next week. Else the odyssey will continue. I have to admit that I'm tiring of Audi antics and beginning to think more seriously about replacing the TT-RS with a car that works. I've owned the TT-RS for about three months now, and between two visits, it's now been at the dealership for close to one of those months. It's continuing right where the S5 left off...

A new turbo?! The cold noise on mine is definitely NOT an issue with the turbo. It very clearly abruptly stops after the first few seconds of driving, so it is something that is controlled.

[- Jeremy -]

A new turbo?! The cold noise on mine is definitely NOT an issue with the turbo. It very clearly abruptly stops after the first few seconds of driving, so it is something that is controlled.

The theory isn't that it's a problem with the Turbo specifically, but that it's a problem with the Wastegate. I don't know why they just didn't replace the Wastegate, but Audi service probably doesn't work like that. They probably receive the Turbo from Borg-Warner as an integrated package.

I understand fortunes' frustration. I'm sure a lot of us will be going through the same thing pretty soon. I hope it solves the problem so you can get the car back and start loving it again.

- Jeremy -

[Marty]

The theory isn't that it's a problem with the Turbo specifically, but that it's a problem with the Wastegate. I don't know why they just didn't replace the Wastegate, but Audi service probably doesn't work like that. They probably receive the Turbo from Borg-Warner as an integrated package.

I understand fortunes' frustration. I'm sure a lot of us will be going through the same thing pretty soon. I hope it solves the problem so you can get the car back and start loving it again.

- Jeremy -

Given the widespread reproduction of the problem (i.e., everyone seems to have the issue), replacing a problem part with a new one isn't going to resolve the issue unless something has been changed in the part to correct the problem from happening again.

I can't imagine how a waste gate could make this sound. It cents back in to the exhaust, and there is no real engine load when the issue occurs.

[JohnLZ7W]

Given the widespread reproduction of the problem (i.e., everyone seems to have the issue), replacing a problem part with a new one isn't going to resolve the issue unless something has been changed in the part to correct the problem from happening again.

I can't imagine how a waste gate could make this sound. It cents back in to the exhaust, and there is no real engine load when the issue occurs.

Could be the wastegate spring or just the valve itself opening but I agree when it happens for me there's no boost being generated so the wastegate should be fully closed. It seems like it should be pretty easy to isolate with the car on a lift since it happens just revving the engine in neutral. Put it in the air at night, then first thing in the morning have someone rev it while someone else listens around the engine.

[fourtunes]

Could be the wastegate spring or just the valve itself opening but I agree when it happens for me there's no boost being generated so the wastegate should be fully closed. It seems like it should be pretty easy to isolate with the car on a lift since it happens just revving the engine in neutral. Put it in the air at night, then first thing in the morning have someone rev it while someone else listens around the engine.

That's what I thought, but it seems that despite several weeks of investigation and several visits from a regional Audi representative, the problem has proven elusive in my case. I don't know of any other owners who've actually dropped their cars off at their dealer for this problem, so progress has been slow overall.

[Marty]

That's what I thought, but it seems that despite several weeks of investigation and several visits from a regional Audi representative, the problem has proven elusive in my case. I don't know of any other owners who've actually dropped their cars off at their dealer for this problem, so progress has been slow overall.

Do you know which mechanic at Steven's Creek is working on your car?