Exhaust - Somethings Blowing but What?

[abbos]

Afternoon,

My w202 has started to make a horrible noise, especially when starting or idle.

I have had a listen and I'm pretty confident it is around the top of the manifold area where it connects into the head. How can I do some more troubleshooting to find out what it is as there seems to be a metal heat shield which is blocking view of it.

When reving the car and holding the revs the sound goes away.

Any ideas?

 

[Howard]

Mine did this (w124) turns out it was a loose exhaust manifold (i had had one fitted a few weeks previous and it had worked loose)

A couple of the bolts are proper fiddly to get to on a w124 (ratchet, extension and angled socket) tightened it up and it went away....

HTH

Failing that , it could be a small crack that is open when the manifold is cold but when it is hot expands enough to seal it .....

 

[donv]

mine did that on a w208 cab the manifold had a slight crack in it on the underbody when the car was warm the sound wasnt to bad but when cold thats when it's at it peak

 

[racall]

Have you a small shock absorber that goes from the head to the fan belt tensioner?, Push the top with a screw driver and see if it stops.

 

[abbos]

For the life of me I can't see anything but after burning my hands a bit I think I have found the problem.

It seems it's possible one of the bolts from the downpipe to the CAT has come loose. I could put the end of my finger between the gap so I'm pretty sure it's that.

Does anyone know anywhere in Maidenhead I can drive in, get them to put the car up, tell them which bolt to tighten and then walk out and maybe throw them a fiver or something?