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High pitched noise
Posted: Wed Jul 05, 2017 7:10 pm
by 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
Re: High pitched noise
Posted: Wed Jul 05, 2017 8:07 pm
by 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 ? .
Re: High pitched noise
Posted: Wed Jul 05, 2017 8:33 pm
by 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
Re: High pitched noise
Posted: Wed Jul 05, 2017 9:19 pm
by Ajc
Could be a turbo issue or a boost leak from somewhere.
Is it using oil or blowing smoke on boost ?
Re: High pitched noise
Posted: Wed Jul 05, 2017 9:44 pm
by Shoppinit
Possibly gearbox ATF cavitation. Check the level. Make sure the right strainer is installed.
Re: High pitched noise
Posted: Wed Jul 05, 2017 10:02 pm
by 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 ?
Re: High pitched noise
Posted: Wed Jul 05, 2017 10:09 pm
by 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.
Re: High pitched noise
Posted: Wed Jul 05, 2017 10:13 pm
by Shoppinit
Does the pitch increase with engine speed or road speed?
Re: High pitched noise
Posted: Wed Jul 05, 2017 10:30 pm
by 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 ...
Re: High pitched noise
Posted: Wed Jul 05, 2017 11:16 pm
by 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?
Re: High pitched noise
Posted: Thu Jul 06, 2017 7:55 am
by 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
Re: High pitched noise
Posted: Thu Jul 06, 2017 10:00 am
by R5XVB
Does your neighbour have a cat?

Re: High pitched noise
Posted: Thu Jul 06, 2017 10:26 am
by simonpoulton
Does it happen when in neutral?
Re: High pitched noise
Posted: Thu Jul 06, 2017 2:33 pm
by 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.
Re: High pitched noise
Posted: Thu Jul 06, 2017 2:36 pm
by chunky79
Ajc wrote: ↑Wed Jul 05, 2017 9:19 pm
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.