mp66226

My car is a 2012 Q5 Premium Plus, 2.0t, about 84K miles on it. Has never had the oil consumption issue, had it scanned about 4 weeks ago at a local euro repair shop that does Audi/VW too (before the symptoms below) and no codes were in it at all.


So, hear is my problem. For the last 2-3 weeks, been hearing a whistling sound only when sitting inside the cabin, but it sounds like it is coming from outside. It is engine related I believe and I was thinking it was maybe a vacuum leak. Then I got a check engine light and a code for lean, checked the PCV and the diaghram was torn. Replaced just the diaghram while I waited on the entire PCV unit. The whistle was still there, got the PCV unit and replace the whole thing, whistle still there but haven't got any more lean codes. For the most part the whistle stays at the same pitch and intensity regardless of the engine speed or car speed. There is a notable exception that points to something engine rather than a mirror or body issue. When stopped, idling, RPM's just below 800, the whistle is slightly higher pitched and less loud/strong/intense. Give it any amount of throttle and the normal pitch and loudness kicks in. I replaced the engine air filter but that didn't help. I also replaced the cabin air filter right before this started but I don't think it is related to that as it makes the noise this even when climate control is turned off. I did notice this morning that it didn't start to whistle until it was approaching normal operating temp, doesn't seem to do it when cold. I also noticed this morning when I ran it thru a car wash that I couldn't hear the sound. I pulled out of the car wash and within 15 seconds I heard it again. I also can not hear it outside the vehicle although it sounds like it is coming from outside when sitting inside and listening to it. I could hear it an up to 3500 rpm last night while trying to isolate it but the highway speed/road noise started to drown it out I think, I think it was still there. A few months ago, it threw a few P0299 codes, but hasn't since. The car, when pushed hard, runs hard so I know boost is there and haven't had any of those codes in 3 months but was wondering about if this could be a diverter valve issue. Again though, nothing really changes with RPM. I thought maybe a belt, but again constant sound/pitch throughout the rpm range kind of seems to nullify that (again, the exception being when stopped and at idle, a slightly higher and quieter pitch).


Any thoughts, guess, suggestions, etc., before I take it in to pay someone to chase a noise?

4SallyPat

Turbo whine

mp66226

Would that not change sound with engine (and turbo) speed? Also, shouldn't I be able to hear that with the hood open and my head down in there?

omegis83

I've got a hissing but mine is only when under half throttle while driving. Your issue may be related to the TSB. Granted, I can't find a dealer that will tell me more about this TSB.

mp66226

Thanks for the thought Sally Pat. I was wondering though since it doesn't change sound, pitch, or volume across the entire RPM or boost range that it probably is not the normal turbo whine? Maybe a diverter valve.


Omega, thanks for the tip on the TSB but mine isn't a hiss at all, and isn't tied to acceleration. Pretty much constant.


One more thing noted over the last couple of days. While it is always near or at operating temperature when it makes the noise, there have been a couple of trips where, when I slow down to the point where I could hear the whistle if there, it isn't there. Maybe 15 or 30 minutes later, get off another highway and again slow down or stop at a stop light and it is back.


If anyone can correct my assumption on the turbo whine suggestion or provide some other input, would be greatly appreciated. Looking at taking it into Audi dealership on Thursday of this week and pay them the brain surgeon rate to look at it. Going to have them check the version of the ECU/Transmission control units too. I get the harsh downshifts and some surging/pulsing under some to neutral load on the highway that I can feel and can see the tach needle just barely swing at the same time.


Again, please help if you can before I have to sell one of my kidneys to pay for the Audi dealership to diagnose! ;-)

omegis83

If you get bored before Thursday, you can dig through the TSBs and see if any are related to your issue. The site below will give you detailed info on each TSB versus checking Safercar.gov

http://www.revbase.com/BBBMotor/

mp66226

OK, so the latest. I changed by DV, it was apparently the original that came on the car from the factory since the local dealership had no record of replacing it and the PO always took it to the dealership for maintenance. It was a rev D valve so was doubtful it would change much since most of what I've researched indicate the rev D valve rarely fails. I noticed a little oil dripping out of the electrical connector (come to think of it, I didn't clean that out before reconnecting). Also, when I removed the valve, the body, a shaft with a spring on it came out but the other parts remained in the engine. Easily removed but it gave me some hope that the valve was bad and maybe replacing it would work. However, still have the whistle although the MPG jumped back up 2-3 mpg where it was earlier in my ownership of this car. Also, noticed on slight acceleration from maybe 45-70mph (might be happening otherwise as well but I haven't noticed it), I am getting the very slight surging, basically in a rhythm or cyclic way, the cycle seeming to repeat every 2-3 seconds or so. Also, the car has had harsh downshifting during slowdown. Both of these have been occurring since I've had it. Gonna look at the N75 valve next. It seems like sometimes I get some pretty strong low-end boost (2500-3000 RPM) but then, not the next time. I'm wondering if something is causing the boost to fluctuate, vacuum leak (whisting?)? So, the next most likely place is N75. I have an OBDII reader that I link to my cell phone. it still jumps to 15psi boost per that connection but, obviously, that is what the ECU is saying, don't know if a boost gauge would be "analog" and is based upon actual pressure? BTW, I know about the Torque Converter potential with the surging issue but am ignoring that until I've exhausted all else. Ignore it and maybe it will go away??? ;-)