High Pitch Whine or Squeal at Start-Up

[rosseich]

1995 ZR1 with 10,000 miles - all original. I'm hearing a high pitch whine or squeal at start-up and first few minutes until the engine is warm. The idler pulley was rebuilt by Marc, and all the other pulleys and components are original. The belt is also new.

I have removed the belt and manually spun the water pump, alternator, power steering pump and AC compressor. All sound/seem normal. Since it is only noticeable when the engine is running at 2000+ RPMs, how can I identify the source of the issue?

I would appreciate your thoughts/advice.

Thanks.

[Mikey]

Have someone else start the car while you listen. You can use an engine stethoscope to isolate noises at each accessory component bearing.

[hotroddaddyo]

Was the noise before the new belt or after?
Is the new belt properly tensioned? Proper size belt.... (length, width, number of ribs)?
Trying spraying belt dressing on belt with engine running... careful!

Do you hear the noise when the engine is running without the belt?
Try another belt.

Any excess lateral play in pulley bearings, water pump shaft, etc.?

[mlipmd]

Are you hearing an air whistle? Does that noise change or disappear if you increase the rpms slightly?

[Young1]

Is squeal with clutch engaged? Or clutch disengaged?