Weird car sound in traffic & under acceleration

[Bagel2003]

Hi,

Can anyone help with a wierd sound that my MK3 2 litre GTI is making? It's like a tinny, vibrating noise similar to pinking (the car pinks already and needs a service). It only seems to do it when the engine's warm and is evident when in 3rd/4th at a lowish speed -also in traffic pulling forward it makes the same noise. I originially thought it was the heat sink under the car but have had it on a ramp and checked all that but all is clear. I've checked the exhaust and that looks fine - all attached and no holes in it.

Could it be the cat?

Whatever the noise is, it's been doing it for ages.

Thanks.

[Overseer]

heat sink? you mean cat heat shield?

[Bagel2003]

Yeah sorry, heat shield - I've adjusted all that (but it wasn't snagging) and it's still making a wierd noise.

I go over a lot of speed ramps (not through choice) and thought I could have caught something on the poxy ramps...!

[jte]

Sounds like a cracked exhaust manifold.  Won't cause any real problems, but without replacing it there's not much you can do to stop the noise.

[Len]

Its is the heatshield up on the manifold.

I have had this problem for 18mths now - learn to live with it! Also the revs at which it happens will change over time. Mine is around 2500-3000 now - when it started it was 3500-4000.

I am told its a pig of a job to sort, because it means taking of the exhaust manifold and they are tricky things as they a fixed with studs and there is a risk of these studs snapping!

[Justins145bhpMK1]

YEah its the heat shied on the cat. Take it to a tyre place and get them to put it on the ramp and cut it off with a oxy torch. Had mine removed and that sorted the problem!