I’m new to the site and honestly need advice or suggestions on the issue I’m having. My car started making squealing noises, so I went ahead and checked the belts and they’re fine. The grooves are intact with no cracks. I’ve replaced both pulleys as well. My next thing was to check the compressor because when I’d turn the AC on the squealing gets worse. The car ended up dead because the battery wasn’t getting enough power from the alternator and when the car was jump started it turned on and was fine so I replaced the alternator. Now, after replacing everything seems like the battery was drained and might’ve gone bad. I’m going to test the battery and see what’s going on. However, I went ahead and took the AC belt off the compressor to see if the noises continued and it does, but it comes in and out at the rate of a heartbeat and is softer compared to before was more of a screeching noise. Anyone know what else could be causing the squealing?

 

Do u have the correct tension on the belt? They will slip if theyre not tight enough.

 

Yes. The belts aren’t the issue. I ruled out the compressor was making the screeching noise and the only one I have on is the serpentine, but the noise continues and sounds like chirping.

 

Take off both belts, spin the pulleys by hand, pay particular attention to the idler and tensioner pulley since they're usually the first to go. (you can't spin the crank pulley by hand so don't do that one

They should spin with no noise, the idler and tensioner should also be stiff and unable to keep spinning endlessly when you give it a good whirl. If you need to know what a new idler/tensioner feels like go down to a local parts store and have them pull one off the shelf so you can feel it.

Squealing is improper tension 99.99% of the time. Rarely it can be caused by a completely seized up pulley.

The AC belt doesn't have an idler, just the tensioner. The primary belt has both an idler and tensioner.

 

Also, belt tension (krikit gauge) for used belts.

Primary belt - 175 lbs
AC belt - 100 lbs

 

Going thru the same problems & ive heard everything but i cant pinpoint the problem. New bando belts, & ive been messing with belt tightening & new idler/tensioner pulleys, cleaned the pulleys. At this point i really dont know what my problem could be either. My accessory belt isnt on as well cause my ac was sounding rough & i found out it was overcharged but all these noises coming from just pulley issues is a headache.

 

Sounds like a bad bearing, spin the idler/tensioners by hand and see if there is any noise.

Strongly recommend going to a parts house first, have them pull any tensioner/idler so you can spin it by hand brand new to see what it SHOULD feel like. They should be sort of stiff with zero noise, and you're usually not able to actually spin the thing and have it keep rotating.