Engine still Screeching

Over the past few months have had a cracked exhaust bracket (horrible noise over 5Krpm) and the very craacked Manifold heatshield replaced and I am still being plagued by the bloody noise

Only happens when engine is hot, when changing gear, or abruptly stepping on the gas there is a screeching noise metallic grinding noise which comes from the engine bay for a split second.
Its most definatly heat related, wont happen when the engine is cold.

I suspect it is a combination of heat, and some sort of physical movement of the engine which is causing the noise. Changing gear or stpeeing on the accelerator cause the engine to physically move, combine it with the heat factor and that is when you get the noise.

I still suspect some exahaust part or something somewhere making contact but if anyone has experienced something similar please let me know becuase its driving me nutty

Sure it isn't belt relatedscreeching.
Can it happen at standstill?

Or even the A/C compressor clutch

Noises are difficult to trace over the Internet!

As per David C post it could be the A/c clutch. Switch off the A/C and see if the noise goes away. The other possible is a bearing failure in the alternator or water pump. Anyone tried posting a sound file??!!!

Thanks for the replies fellas,

I wish I could take a sound clip, you can only really hear it with the window down, even then the eind noise etc would make it impossible to pick up on a mic.

The A/C clutch?? whats that? I dont know about that but I never use the climate control (or at least with the compressor on anyway).

The noise is NOT there at a standstill when I rev the engine up and down. SO I think that may eliminate a belt related noise. Not sure.

One interesting thing is that the noise only really occurrs when I change up or down gears circa 2.5-3K RPM, or if I put my foot down on the accelerator around the same rev range. If I change gears or acclerate when high in the rev range 4K+ the noise ISNT there.
I knwo that heatshields etc resonate at certain revs but that has been replaced already.

Any further suggestions would be welcome.

Sorry but as David said without hearing the noise it’s impossible to diagnose the problem. The only thing I can add is that if you are sure that it’s not the A/C as it is switched off and you describe the noise as a ‘screech’ I would hazard a guess that it is belt related. Check all the visible belts for condition and correct tension. Beyond that we are crystal ball gazing so you will need to get a garage to look at it.

Originally Posted by renone

Sorry but as David said without hearing the noise it’s impossible to diagnose the problem. The only thing I can add is that if you are sure that it’s not the A/C as it is switched off and you describe the noise as a ‘screech’ I would hazard a guess that it is belt related. Check all the visible belts for condition and correct tension. Beyond that we are crystal ball gazing so you will need to get a garage to look at it.

Like he said, sounds belt related to me. Most likely auxillary belt as these sometimes get neglected when changing other belts, could be a bit glazed.