Erkmed XJ

Alright, this only happens when its been sitting out in the sun (hot weather) all day. I go start it up and it makes a small chirp then silent for a good 5-10 seconds then a load screeching/squealing for a good 30-45 seconds and its the loudest "belt squeal" ive ever heard. Then after that 45 seconds its back to normal amd dont hear it again untill the next hot day

Nperryman

Is your ac on during this squeal? After all you said it was a hot day.

Erkmed XJ

No, it was off

RTorrez1

Start by checking your belt for glazing if none start it and listen to see if one of the pulleys seem to be making the noise. You can also pull the belt and check all the pulleys to see if they are loose. Don't forget the most common reasons the belt needs to be tightened.

Erkmed XJ

The belt is like new and the squeel doesnt give me enough time to start and then go to check and see where its comming from and the belt seems tight

RTorrez1

You may want to pick up a belt tension gauge from the auto parts store and start with that. I know the belt on the 4.0 need to be really tight. If still have the problem after that, pull the belt off and check all the pulleys to see if they feel lose also see if they seem to make any strange sound when you spin them by hand. It could also be a bad bearing one one of them.

Erkmed XJ

I lied it might have been, i had the ac off today when i started and there was no squeal turned it on say 2 min down the road it squealed for 2 secs then stopped

salad

Have you noticed your voltage dip low (if you don't have the idiot lights)? I get the same sort of behaviour when my alternator gets wet

Nperryman

Hmm. It could be the compressor bearing. When was the last time you had the a/c recharged with refrigerant? Is there anyone that can start the jeep for you with the ac off and then turn it on? If so look at the little clutch disc at the front of the compressor by the pulley and listen close to see if that's where it's coming from. I have the same squeal, and it's from my compressor, I think it's just because I don't have any refrigerant in the system to lubricate the bearing and clutch and I have to jump the low pressure switch to even get it turned on. But I'm not sure. It might be a bad compressor bearing.

Erkmed XJ

I got dummy lights haha and it was on a dry day

Erkmed XJ

not sure when it was recharged or how long ea charge lasts but i bought it a few months ago and it only has 58k miles if that means anything. Also it only happens when its 80+ or so not only when the ac is on

tjwalker

Belt is absolutely the #1 suspect for a little chirping and squeaking.

Replace it with a Goodyear Gatorback if the current belt has 60k or more on it.

And be darn sure the belt is tight enough. As mentioned, the 4.0 likes a tight belt.

Erkmed XJ

Its a new belr, well mewr few thousand miles on it

Moncheche

I don't have my FSM handy but the torque required for proper adjustment is one half turn past 'holy crap is this tight'. Seriously. First time I used my torque wrench to set my belt, I was sure the FSM was wrong. It's not.

BotakBeng

Get this from Napa.