On a supercharged 4l XKR I am suffering a loud metallic screech at about 3000rpm onwards.

Before I take it to the local garage what do people recon?

Supercharger?
Water pump?
Alternator?

No sign of any noise at lower revs, and in sport mode just starts at gear change, dont think its the gearbox as the noise happens in neutral as well.

 

Slipping belt?

 

I do hope so, but I fear not as there is a metallic undertone to it. This weekend I will find out for sure!

 

Idler pulley! bearings shot

 

Idler was also my next suggestion.

 

Thanks for that will be the first place I look

 

A slipping alternator belt has a sound instantly recognizable to any mechanic. Best change it, as if you just tighten it there will be further trouble soon. They feel surprizingly tight when correctly adjusted, this is because of the heavy load charge current just after start-up. While belt is off, of course check for slop in bearings.
Leedsman.

 

Off to the garage/shop and guess what, nothing, no funny noises absolutely quiet. 300 miles done over weekend as well and nothing at all.

Thing is the next door neighbours cat has disappeared