Rattling noise between 2500-3000rpm...

[IntriguedUser]

I drive a 2005 Vauxhall Corsa 1.8 sri, it's belt driven and has 109,000 miles on it.

I'm getting a rattling noise between 2500-3000rpm, it sounds like lots of bits of metal rattling around inside something.

Key things to note:

- It only happens when the ENGINE IS COLD. It also lessens as the engine warms up more and increases as the engine cools.

- Sounds like its coming from the belt area

I'm thinking metal expands when it gets hotter, so a lose bolt could effectively become tight again when hot?

Any ideas of where to start/what to check. I think a key thing here is the noise goes away when engine is hot and it only happens between certain revs. Could be a lose bolt/screw resonating between certain revs?

Thanks guys for any feedback. I have posted on the Corsa C forum but it's pretty dead over there these days, and it might not be specific to Corsas...

[nails1979]

Heat shield on the exhaust. Probably manifold or cat(s).

[IntriguedUser]

Went around to a few garages and all of them said it could be the bearings in the pulley? I'm going to get the belt changed as it needs to be done anyway and I'll go from there. Thanks.