Whining noise coming from airbox area

[jackyaudi]

Any one experienced this before? If I remove the air intake the noise becomes more obvious, it sounds like "NNNNNNNNNNNN". I have not heard it this summer. I only noticed it today.

[rocketheavy]

its called a turbo lol

[Phorte]

it sounds like "NNNNNNNNNNNN"

pwuhahahahaha.

[jackyaudi]

its called a turbo lol

You are not serious are you? I had my hood open 100 times and this is the first time I hear this noise when the engine is running on idle. What gives?

[AudiA4Turbo22]

SAI whines because it is a motor that sucks in air at idle during cold starts should go away after 20sec.

[jackyaudi]

Well, I heard it after being on the highway for a while, it does not sound too good, its like something is struggling. Anyone else heard this before?

[AudiA4Turbo22]

maybe ur SAI has been shorted and is constantly running is ur idle normal?

[OneBadAudi]

Are u still boosting the correct pressure?
Turbo may be going Boom...but i could be wrong, been wrong plenty of times.

[boravr6]

Well, I heard it after being on the highway for a while, it does not sound too good, its like something is struggling. Anyone else heard this before?

is the noise accompanied by some vibration in the steering? I might know what it is if it does! ...

[F16HTON]

Take it to the dealer and have them check it out.

[jackyaudi]

Thanks for the replies guys.

Idle is 100% normal, RPM and vibration wise.

boravr6: no vibrations at the steering.

Turbo feels and sounds just fine when driving. It got replaced like 3 months ago along with the cat by one of the dealers.

I just started the car again after it rested for like 2 hours, and I did not hear that whining noise at all. Temperature was about 70C, and the noise just was not there anymore. So am guessing the noise happened when the car was very warm (coz the radiator fans were running), or because of something else..

400HPA4: ya that would be my last bet when I take it in for oil leak issue next month.

[Jibberific]

electric fan going out maybe? its in that area

[A4ringedONE8T]

The evap purge solenoid makes a humming/ticking noise at times

[jackyaudi]

Jibberific: I thought of that, but ruled it out when I put my ear on the airbox and heard the whining very clearly.. its as if its coming from right inside the airbox

[whiteUSPflow]

is the noise accompanied by some vibration in the steering? I might know what it is if it does! ...

i think i have that problem just started 2 days ago its a whinning when the turbo spools but its kinda high pitch and while accelerating i do feel a little vibration. let me know if you guys have any ideas.

[Jim@STaSIS]

when turbo's begin to fail they will often make whining / whistling noises. the infamous 'dentist drill' sounds. typically it's on decel at certain rpm's where it shows up first.

let's hope it's just a loose belt!

[boravr6]

i think i have that problem just started 2 days ago its a whinning when the turbo spools but its kinda high pitch and while accelerating i do feel a little vibration. let me know if you guys have any ideas.

I had a whineing noise that started last week. Coincidentally it started when the cold weather rolled in....

Check your power steering fluid. Its normal that the level of fluid goes down with cold weather!

here is the link i found on this issue

http://dejong947.com/audi/tsb/audi.tb.48-05-01.pdf

[dougyfresh]

Jibberific: I thought of that, but ruled it out when I put my ear on the airbox and heard the whining very clearly.. its as if its coming from right inside the airbox

Did you listen under the airbox by where the turbo is? You could pull the airbox out and listen to the TIP. If it is very pronounced then there is a good possibility there is an issue with your turbo. Has Martin looked at it yet?

How many miles are on your car?

[jackyaudi]

Did you listen under the airbox by where the turbo is? You could pull the airbox out and listen to the TIP. If it is very pronounced then there is a good possibility there is an issue with your turbo. Has Martin looked at it yet?

How many miles are on your car?

Doug,

Well, since I dont have a garage and its freezing outside, I cannot really stay for long, so I did not remove the airbox yet. When you say listen to the TIP, am not sure what do you mean

No Martin has not looked at it yet.

I dropped off my GF to work today and when I came back opened the hood and did not hear that whining noise at all. Engine was obviously warm.

If its with the Turbo would it not make the noise all the time??

[dougyfresh]

Doug,

Well, since I dont have a garage and its freezing outside, I cannot really stay for long, so I did not remove the airbox yet. When you say listen to the TIP, am not sure what do you mean Turbo Inlet Pipe.. the line going from the airbox down to the turbo inlet. If the turbo is on its way out you'll hear the noises through the TIP.

No Martin has not looked at it yet.

I dropped off my GF to work today and when I came back opened the hood and did not hear that whining noise at all. Engine was obviously warm. Sounds like an SAI thing like Kirk suggested.. meaning it occurs at cold start.

If its with the Turbo would it not make the noise all the time?? Yes

see responses in blue.

[jackyaudi]

maybe ur SAI has been shorted and is constantly running is ur idle normal?

Do you think the SAI would kick in when the car is really warm? Where is the motor for the SAI, I want to check it or unplug it and see if the noise persists..


BTW, I either have to drive the car REALLY hard or for a long distance to hear the humming/whining noise coming as if its inside the airbox.. With normal driving, up to 3500RPM, and when the engine is fully warm, I dont hear anything at all. And its only obvious if I open the hood and listen to it.

I really freaking hope its not Mr. Turbo.

[dougyfresh]

Do you think the SAI would kick in when the car is really warm? Where is the motor for the SAI, I want to check it or unplug it and see if the noise persists..

No. There is no reason for SAI to kick on once the engine is warmed up. It is only used for cold starts.

The pump resides underneath your passenger side headlight near the frame rail.

[AudiA4Turbo22]

the SAI makes a loud whining noise like ur fans kicked it. It is right under the air box area so that's probably what it is.

[jackyaudi]

the SAI makes a loud whining noise like ur fans kicked it. It is right under the air box area so that's probably what it is.

Question is, why would it be working and whining when engine is really warm.. am getting confused now. Does anyone heard their Turbo make such noise at idle after driving the car hard?

[AudiA4Turbo22]

^^the sensor that turns it on and off when the temp is reached is probably lunch so that may be it.

[jackyaudi]

^^the sensor that turns it on and off when the temp is reached is probably lunch so that may be it.

I see.. but lets say for a second that the sensor is bad, and that the SAI pump is working overtime, is it normal for the SAI pump to make that humming/whining noise or not?

Best way is to disconnect that SAI motor altogether and to listen if I hear the noise again. Time to research on how to do that. I just really hope its nothing related to the Turbo, coz its hard to convince the dealer to change it.

EDIT: unless there is a fuse for the SAI pump I can just take off. That would be the easiest thing.

Thanks Doug & AudiA4Turbo22 for the help.

[jackyaudi]

Thanks to a pic from A4mods, there is only to connections made to the air box, one for the TIP, and the other is the SAI pump feed as the pic shows:



Now am assuming that the SAI pump feed will actually push air into the air box and the TIP will suck air into the Turbo. So disconnecting both at a time should hopefully pinpoint where the noise is coming from: Turbo or SAI pump. If its the SAI I wont even bother with it. It can die or I will leave it as is. If its the Turbo, then.. well, we have some trouble.

[jackyaudi]

Update:

Thanks to FourRings80, we were able to find out the noise was not coming from the Turbo nor SAI pump feed, but rather if you put your fingertip on the PCV return line, the noise goes away, but we did not have more time to exactly find where its coming from. Guesses are: some leak or some bad valve somewhere.

The noise was heard clearly from the airbox coz the PCV return connecting to the TIP.

I will post the fix once we find it for future reference.

[jackyaudi]

Update/Problem solved:

Here is the illustration: #15 is where the noise was coming from, gets more clear after you disconnecting it. To hear the noise even more loudly and clearly, one could open the oil cap on top of the engine when the engine is running at idle. It sounds like its struggling in there. The part that was totally blocked (both ways) was the "bleeder valve" shown in red circle. Replacing it fixed the problem altogether. Its a $15 USD part.




EDIT: No intake removal was needed on my car (2002).

[J-jizzle]

What is the number '1' part? for the update.

[jackyaudi]

What is the number '1' part? for the update.

Thats the oil filter bracket, but which part are you looking for so I get the part number>

[J-jizzle]

^^^Dang I should of known that. I'm not looking for a part I was just wondering where the lines where running from.

[Nerney]

its called a turbo lol

Haha I saw this title and I that was the first thing that crossed my mind... NICEEEE

[jackyaudi]

had nothing to do with the Turbo, sorry for you guys