Whistle noise when cold

[nick_mcuk]

So not a big problem and doesnt affect the running:

So when the car is cold there is a funny sort of whistle noise when on overrun...its coming from the front for sure. It vanishes when the car is up to temp.

As said it doesn't affect the running...just kinda annoying, any ideas people? Its a standard Chimaera 400.

It sounds like its coming from the passenger side dash area....once the cars up to temp it vanishes.

Any ideas or people that have had similar?

[Loubaruch]

Sounds like an exhaust manifold gasket especially as it stops when the engine is warm.

Plenty of info on here re changing the gaskets, not the most pleasant of jobs.

This may help:

http://www.bertram-hill.com/replacing-exhaust-gask...

[nick_mcuk]

Loubaruch said:

Sounds like an exhaust manifold gasket especially as it stops when the engine is warm.

Plenty of info on here re changing the gaskets, not the most pleasant of jobs.

This may help:

http://www.bertram-hill.com/replacing-exhaust-gask...

Thanks for this...i thought that too but in the past (on my 205 GTI) when the fanni-mould gasket leaked it would vanish after a minute or 2 at most at idle...this wont go till the car has gotten to 70 degrees or more.

I will have a look and poke before head off to get my little lad from Nursery today...if its leaking I would think that I would be able to smell exhaust fumes right?

[N7GTX]

Not necessarily. If you have fitted heat boots in place of the extenders, pull them off and look to see if there is carbon/black soot on any of them. This is a giveaway of a gasket failure.
If you are still on extenders, again look for soot on any of them.
If you have the original exhaust manifolds they crack in between the welds where all the pipes meet.

[Hedgehopper]

Loose / leaking idle screw on the plenum?

[carsy]

Hedgehopper said:

Loose / leaking idle screw on the plenum?

Yep, the idle air bye pass screw can cause a whistling sound. If its that just adjust it very slightly until it clears.

[nick_mcuk]

carsy said:

Yep, the idle air bye pass screw can cause a whistling sound. If its that just adjust it very slightly until it clears.

Is that the one on the inlet plenum...got a hex head in a recessed hole?

[carsy]

Thats the one.

[angus337]

Noticed the idle screw on mine is a little loose, and now and again I get a bit of a whistle. This may be a result of the number of times I've adjusted it recently.

I also suspect that the screw is moving over the course of a drive and affecting the idle. Last time I checked it after a drive it was almost fully closed, resulting in a hunting idle. I've marked the position now so will see if it moves next time out.

[carsy]

Mine did similar. I wrapped a bit of ptfe tape around the threads to help give some resistance. However since going to a Bosch 2 wire idle valve ive closed it off completely and just set the idle valve to bleed the needed air in.

[Steve_D]

You need a product called Kilopoise manufactured by Rocol.
It is a paste which works much like Loctite but does not set so you can re-adjust as often as you like.

Steve