Seprentine Belt Squeaks with A/C On

[jheissle]

I have a 1998 Jeep Cherokee. When I start the car and turn on the A/C the belt squeaks and I hear a grinding sound under the hood. If I turn the A/C off the squeaking ends. After about 20 seconds of driving the car, I can turn the A/C on and there is no squeaking.

The belt was replaced only 4,000 miles ago. Any suggestions?

Thanks

[zeppK2]

my 97 used to do the exact same thing...when the A/C was on it would suqeek really loud and high pitched and when i stepped on the gas it got even worse, and after driving around for a while it stopped...no grinding though.

anyway, how i got ride of it...if you look under the engine you should see a big rubber mat type shield that protects you engine from the bottom (just to keep mud and all away), in my case it was rubbing up against the belt and all i had to do was zip tie it to the side and out of the way...problem solved, for me anyway...good luck, if it was like my case it was loud and quite embarrassing.

[tblack]

The belt was replaced only 4,000 miles ago. Any suggestions?

Take it back to whoever installed it and have them check it out. What you are describing sounds like serpentine belt trouble and if you replaced it that recently, maybe it was not installed correctly.

[SteveB05]

I'm gonna guess that the grinding sound is actually the tensioner vibrating. Take the belt off and spray some WD-40 on the tensioner bracket and spring (not the pulley side) Then move it back and forth, all the way a few times, then put the belt back on and see what goes. Also, while you have the belt off, check all pullies for play (grab the top and try to move forward and back).

I would get a warranty replacement of the belt no matter what. Even if it is the tesioner or something else, you've hardened the belt from the slipping and shortened its life.

[4x4grey88]

The seprentine belt is slipping and that is why you hear the squeaking. When you turn on the AC you add the stress (or tension) to the belt. That is why it squeaks.

My seprentine belt squeaks when I start it up and normally stops squeaking after a moment. I adjusted the tension and it stopped.


You can get some belt dressing to help the gripping of the belt too.

[AlohaBra]

Originally Posted by 4x4grey88

The seprentine belt is slipping and that is why you hear the squeaking. When you turn on the AC you add the stress (or tension) to the belt. That is why it squeaks.

My seprentine belt squeaks when I start it up and normally stops squeaking after a moment. I adjusted the tension and it stopped.


You can get some belt dressing to help the gripping of the belt too.

My 97 4L has 122K on it. The tensioner has a sealed non servicable bearing than can wear out. I just replaced the tensioner bearing (cost $12 with the pulley).

You can buy the whole pulley with bearing if you take it off and match it. Or you can just replace the beariing. I bought the whole thing but the pulley was wrong, so I pressed out the new bearing and installed it on the old pulley. I used a large socket and a tubular jack stand. Make sure you don't hammer on the bearing part just the outside sleeve part.

Then you can retension the belt properly. Problem fixed. If it squeaks after a while, retension because the belt will stretch. Tip: use a nylon tie wrap to hold the Serp-belt in place while you get the parts and for safety, disconnect the battery first.

[bebert]

Same problem. My '01 XJ doesn't have a self-tensioning pully, so the monkey who put the belt on first broke the bolt on the tensioner. Moron? Did that by not loosening the nut first. Replaced the nut and the belt. Same noise. Finally I suggested tightening the belt rather than leaving it loose as was suggested by the monkey. Problem fixed - sort of. Still a bit loose so I can't turn on A/C for the first few seconds b/c of squeak. Oh, also, the monkey broke a fan blade on the electric fan in front of the power steering pump while attempting to loosen the nut he replaced after breaking the first bolt (neglected to mention that flub up to me). So, when that kicks on there's a nice vibration that resonates throughout. I need to replace that fan ~ $70.

[SteveB05]

No...monkey needs to replace the fan. Does he work for a shop, or is he independent?

[bebert]

Originally Posted by SteveB05

No...monkey needs to replace the fan. Does he work for a shop, or is he independent?

You're right, he does. However, at this point (after he's flubbed-up twice - 1) incorrectly installed belt, 2) broke the nut/bolt on pully) I really don't want him near my engine.

BTW, he's the owner of a lube shop. It took him about 2-3 hours to finally take my advice and tighten the damn thing. First he thought the pully was bad. Ok, but if that's the case, why only noise when the A/C is powered on? Why did the noise stop for a time when I applied belt dressing? Leaving it loose didn't make any sense to me. The belt will stretch a little anyway as it ages, no?

The moral of the story is to get the belt installed by a knowledgeable person. Or, better yet, do it yourself and learn in the process.

[AlmostStock]

Belt dressing will not help on a serpentine belt. If proper tension will not correct the squeaking then one or more of the pulleys are out of line or one of the accessories are starting to fail.

[SteveB05]

I understand, but he can still pay for the part! Especially if he is on account with any wherehouses...he will get it cheaper than you can.

[bebert]

Roger that Steve. I went ahead and installed a new fan anyway. Fixed my problem. However, I'm taking my business elsewhere. I understand that people screw up but the failure to disclose the damage is what really gets me.

[boldbones]

Same thing is happening to my 1995 Toyota Tacoma. There is a bad squeal from the A/C compressor. I am looking into replacing A/C compressor shaft seal.