High Pitch Squeal From Engine with Belts Off
 

I replaced my serpentine belt back a few months ago and I started getting a low pitch chirp that now has tun into a high pitch squeal. I disconnected the belt and started the engine because the squeal was hard to pin point. With the belt off and the engine running I have the squeal. Now, it only starts after the engine has run for more than 20 minutes and it has reached operating temperature. The odd thing is when you race the engine up the squeal will disappear and even quit. Slowly returning as a chirp, quickly into a squeal. Any thoughts. :(

Just for the hell of it you should check every spark plug torque, it solved my strange noise and two were loose.

Problem is, it starts after the engine has been running for over 20 minutes. The spark plugs chirp when loose not squeal to high heaven. Thanks for the input...I had replaced a few tubes not more than 200 miles ago so I know the spark plugs are tight. ;)

Best guess without hearing it... worn timing chain tensioner guides. A common problem.

what is the mileage?

2000S...3.2 ltr...tip...68,000

AOS needs replacing.

Yes, I just ran the engine until it started squealing...loosen the oil cap up and it stopped. Looks like I will replace here soon, was going to change the oil and install a new fuel filter, so I will do this all at once. Thanks. :cheers:

When you replace the AOS, replace the hose that connects to it (not the little bellows that's on the bottom of the separator). Mine had a small crack in it and that is what caused the squeal after I replaced the bad AOS :cheers: .

I purchased everything but bottom hose. Seems no one changes it.

Air/Oil Separator
 

This definately sounds like the problem I had a few months ago. It turnred out to be the Air/Oil Separator. If you let it go too far you will see more smoke comming from your exhaust. It is always a good idea to replace all associated hoses while you have it open.
Not a big expense to fix. :cheers: