Couple of days ago my Jeep started making strange rattling noise. When I open the hood it sounds like the rattling noise is coming from the air conditioner compressor or the alternator that sits right under the compressor.

My A/C blows cold air and when I turn my ac unit off the rattling noise does not stop.

I have very little experience with A/C systems, so any advice would be greatly appreciated.

-J
-Jeep Grand Cherokee 1995

You can try to isolate the noise with a mechanics stethoscope or a l o n g screwdriver.
Or disconnect the serpentine belt and spin all the pulleys by hand, then listen and feel.

[QUOTE=Bob D.]......or a l o n g screwdriver.QUOTE]

Hi Bob,

Thanks for the answer. . . I have a qestion about the screwdriver, how would i do that?

-J

You use it (carefully placed!) kind of like a stethoscope. Put the end of the screwdriver on your suspicious item and put your ear to the handle. The sound transmits up the screwdriver quite well.

Obviously not for items that turn. :grinno:

Check underneath and see if the outer shield on your cat is rattling.

also watch the belt tensioner closely. Under load, it might start vibrating if it is getting week.

Thank you eveyone for your help!!!! I was able to locate the noise, It was the top pulleys (all the bearings where gone).

A $20 problem took me half a day and several bleeding knuckles because of the serpentine belt. I don't think my model has a belt tension-er so i had to manually force the belt back.

If you folks have any suggestions about the belt i would greatly appreciate it (just for future reference).

Again, thank you everyone for your help.

-J

Underneath the power steering pump is a bolt that when you turn it shifts it's location and loosens tension on the serpentine belt. You will find a locknut on the bracket you want to have undone before you loosen.

Underneath the power steering pump is a bolt that when you turn it shifts it's location and loosens tension on the serpentine belt. You will find a locknut on the bracket you want to have undone before you loosen.

Thank you bringselpup, that's good info to know. I will take that path next time.