Fan clutch

Sounds like 2 different problems.....,

Fan stuck on with ac sounds like high pressure switch/sensor...

and over 1500 rpms belts squealing sounds like loose belts.....


But that’s a guess...:-/

 

And - depends on humidity/heat. AC should cycle the fan, but in high heat mine stays on for long periods.

Belts squealing, personally I’d replace them. I’ve used toothpaste to quiet them before, but ultimately changed them out.

 

The screeching sound is caused by the belts slipping when the fan engages into high speed.

The belt or belts may be glazed or loose which is causing the screeching sound.

Either tighten the belt, replace the belt tensioner, or replace the belt, it all depends on your determination after inspecting the parts.

 

Probably what was already mentioned for what sounds like two different problems. I have also seen worn pulley grooves cause some of these type problems. A new belt usually only fixes that problem for a short time. Usually the alternator and I know that is not what you expect. Probably not but look at it.

 

Don't know that I've ever laid eyes on a 97 Detroit, but if it has a belt tensioner that hasn't been replaced in a long time, it could be the problem as well. Tap it with a hammer handle to help it tighten. If it stops squeeling, change the tensioner.

 

Shouldn’t be staying on for more than about 10-15 seconds bud even on a 95 degree day. Your condenser is probably plugged or debris in there. I recommend getting a heat gun and checking for cold spots all throughout your condenser

 

Mine has stayed on longer on hot days. Squealing: loose belts

 

The alternator serves as the tensioner on my 97 Detroit.