High pitched noise

[nai]

Hi all so I'm back in an rs6 c5 .....

I have a slight issue and am trying to locate ...

On normal driving and heavy acceleration it sounds like the cars got a supercharger very high pitch whining noise and goes up with rpm then tails off and then comes back more noticeable after the car has warmed up ....from what iv noticed it gets louder sometimes on a right hand bend



Anyone experienced this? Any help appreciated

Thanks

[Ajc]

Could it be a pully or tensioner on it a way out? . Does it make any difference with the air con on/off ?
Does it do it when stationary ? Or only when moving? .
Does it make any difference with more electrical items turned on ? .

[nai]

Aircon don't work needs gas will be doing that this week

I did suspect a pulley or tensioner but if I rev the car in idle it sounds fine

On load sounds like a supercharger

[Ajc]

Could be a turbo issue or a boost leak from somewhere.
Is it using oil or blowing smoke on boost ?

[Shoppinit]

Possibly gearbox ATF cavitation. Check the level. Make sure the right strainer is installed.

[nai]

Gearbox is shifting ok don't seem like any issues there ?

How do I check the oil level ? By removing the plug while car is running ?

No smoke blowing boost fine can hear the noise after the car has warmed up ....

Power steering maybe ?

[Shoppinit]

Maybe power steering. Checked the level?

Checking the ATF is a bit involved. Depending on how DIY you are you might be better off getting a specialist to do it.

Eliminate the other possible causes first. Could be belt noise.

[Shoppinit]

Does the pitch increase with engine speed or road speed?

[nai]

Ok I'll give the rest of it a go.... can't hear anything on idle

Yes it increases with rpm soecially when I change gear down becomes more apparent ...

[chunky79]

Silly question, you're talking about external of the passenger compartment?
You're not talking about amp whine from the radio are you?

If external, I'd go with power steering as Shopp suggested. Easy to check the level in the engine bay.
How long you had the car? Has it got the correct fluid in?

[nai]

Hi chunky79 iv had the car about 2 weeks power steering fluid seems to the correct level with the green hydraulic fluid innit looks clean .... I have a slight whine while turning steering nothing major

Sorry yes talking about external noise

The only way I can describe it is sounds like a mini supercharger

Happens more at high revs and sometimes on a right hand sweeping bend

Also I have that horrible rattle on cold start which I believe is the cam chain on the back? Could that be the issue maybe wrong engine oil ?

What oil is best for our cars ?

I'm thinking the following

Chain tensioner
Power steering
Front diff
Aux belt tensioner
Cambelt tensioner

[R5XVB]

Does your neighbour have a cat?

[simonpoulton]

Does it happen when in neutral?

[chunky79]

If you can get underneath and whip the aux belt off (there's an auto tensioner) this may help you pin point the sound. Could be the alternator.

[chunky79]

Could be a turbo issue or a boost leak from somewhere.
Is it using oil or blowing smoke on boost ?

Sorry, just read through again.

From your comment that it seems to do it under load, this is a good place to start. Check your intercooler/ pipes and vacuum hoses.