Exhaust noise?

[VK SL 3800]

Got this really annoying noise coming from somewhere in the exhaust i think, its really hard to track as it only sometimes does it and only at idle and soemtimes when you first touch the throttle. Sounds sort of like a hissing ring/ metallic ring if that makes sense. Never when cold, when you pull up sometimes and its really loud and then goes away after about a minute of idling, so when you get out to have a poke about it goes away before you can find it, with the bonnet shut it sounds like its coming from underneath level with the doors, bonnet open sounds sort of everywhere on the carbie/ manifold side, but the manifold gasket is not leaking for sure.
Any ideas?

 

[DerekP]

Could be a loose baffle in the centre muffler.

 

[clutch]

a hissing noise? does it sound like its coming from the engine bay at all? if so, could be a vacuum leak somewhere...

otherwise, go over your exhaust check for holes and leaks, tighten bolts.

 

[VK SL 3800]

I was thinking maybe a baffle in the muffler echoing up the pipes to the engine bay, hissing probably wasnt the best way to describe it, very hard to describe. Definitely doent have any vacuum leaks as i spent ages trying to figure out where a high pitch whistle was coming from under the dash, had a pin hole in a section of the hose so i checked over all the vacuum hoses for any more leaks. I will have to investigate further.........

 

[whats up]

That could be your air con switch,same thing happened to mine and when you remove the actual unit from the dash you have to be careful as there are about 6 or 7 vac lines going in and they are numbered.
What I did when I replaced mine was I extended the lines (cheap to buy) so it made it easier to see what goes where.Good luck
PS my air con works beautiful.

 

[VK SL 3800]

Ok, Found out what was making the noise, it was the little arm that actuates the exhaust flap vibrating ever so slightly and causing a ringing noise which echoed around the engine bay.