Whenever I turn the defroster on my belt starts screeching. I have a 99 xj sport and I just replaced the clutch fan and the radiator and this didn't happened before that also has 206k on it. Any reason why?

 

Strange, check the condition/tension of your belt?

 

Tried tightening the belt and it didn't work

 

Is your tensioner siezed up?

 

No everything works it just screeched really loud. I'm gonna try to loosen the belt today to see if that fixes it

 

The 4.0 is somewhat picky about belts in my experience. I've had good luck with Dayco, Napa (typically made by Dayco), and Mopar belts. Avoid the cheap parts house belts if possible. Also, the 4.0 has the highest belt tension of any vehicle I've ever owned. Search for squeaking belt or look at the bottom of the page in the "similar threads" section for more ideas.

 

Try a Goodyear Gatorback belt. Fixed my problem.

Flash

 

By any chance is your A/C compressor siezed?

 

I don't know. How can I tell if it is?

 

Pop the hood, start the motor and look at the A/C compressor clutch. Make sure it is spinning freely. Turn on the defroster, and then go look at it again. The compressor turns on when you turn on the A/C or the defrost. If the compressor is seized, it wont spin when it clutches in.

 

sometimes, if you spray some belt dressing on it the noise goes away.

 

It must have been some left over wd40 on the belt cause it started happening right after I replaced the radiator and the clutch fan. I took the belt off and sprayed everything with wd40. It just stopped the other day. Thanks for all the help

 

Ok my turn. I have a 97 ZJ 4.0L
Today my idler pulley siezed up. And the belt snapped. Drove it about a mile and a half to the house. Got new belt and pulley. But when I put everything back in it is screeching like crazy. Quieted down after a few minutes( but only after I scrapped the scrap off of the other idler puller) and only at idle. If I hit throttle is screeches loud. Do I need to just let it break in?

On a seperate note I noticed the my voltage is on around 12-12.5( normally 14. Also the jeep went from 100 degrees to 210 in only 45-75 seconds of idling. Should I be concerned or give it a few miles to run and even out?

Don't know that it would make a difference but last night I had to pull two buddys out of some nasty sand and had to do several really hard snatches. If this might have caused a problem, please let me know