Weird engine noise

[Tommo]

Hi all

I went for a drive last night, got home and noticed a weird metallic scraping noise coming from the engine, on closer inspection it sounds like it's coming from underneath near the manifold, downpipe and cat. Any ideas? I've done a search on here and found a similar post (cliokiz) which had the same noise which turned out to be the gasket between manifold and downpipe? Do you think it is this? Anything else it could be? How easy is it to fix? Car runs perfect apart from the noise, doesn't sound nice though...

[northy]

nothing is rubbing on your driveshaft - does the noise stay the same or speed up?

[Tommo]

Noise stays the same mate regardless of speed, it does it at idle too

[cliokiz]

It happened to mine but only when the engine was under load. I didn't believe it was that gasket but it sounded just as if the alternator fins were just scraping something whent the engine tilted. Changed gasket and never heard it again. Very weird.

The alternator fins aren't scraping against anything are they?

You said the pitch/speed of the scraping stays the same regardless of what revolutions the engine is doing? Surely that can't be the case?

[Tommo]

I'll have a proper look tonight, I'm pretty sure the noise didn't change with engine speed, but will double check. To me it sounds like something metallic has come loose and is scraping on something, but couldn't see anything obvious. It's going down to the garage on Tuesday for them to look at it so I'd like to have an idea of what it could be before they are leashed on it.

[Tommo]

This turned out to be the manifold heat shield.... nothing expensive luckily