Belts Screeching

Okay guys I need some help. On my 3.4L I’ve changed all my belts twice with new belts. Currently have the continental belts installed. I’m trying to find the source of screeching when I turn the truck on. It lasts about 5-30 seconds seems like when I throw it into gear it quiets down and goes away. And seems to only happen after the car sits. So screeches at a cold state. I’ve changed belts twice. Changed the AC tensioner yesterday. Could it be a issue of the belts being to tight? Thinking maybe it could be the alternator bearings but it’s not a consistent sound or some other pulley. But it run very quiet and smooth once the screeching stops. Any ideas would be super helpful. I’ve taken off and on belts and tightened and loosened so many times .

 

Get a can of silicone spray and spray each moving pulley.

 

I had almost the same exact issue that turned out to be a bad bearing. In my case it was the alternator. After it is done squealing shut it down and put your hand on the alternator, fan, and compressor bearings and see if any of them are particularly warm. It may be an omen of bearings to fail. It was for me.

 

It's been the AC compressor on a couple of vehicles for me over the years.

My automotives professor at university, Doc Schraeder, used to say, "When they start talking to you, they're getting ready to break." That's generally been true -- but as you've done the belts, that's probably not your case. Check your tensions, yes, but then start looking for a bad bearing in one of the driven components.

 

Sitting is causing one of those bearing to get tight . Heavy load on the alternator after starting.

Have any of the belts glazed on the inside compounding the problem a squealing belt is a slipping belt