Whining AC?

[Mikel]

Hi,
The AC in my 95 XJ (4.0 5sp) makes a whining noise that is quite noticeable, although not excessive (yet). Is this a normal condition? Is this a sign that the compressor is going bad?
Thanks.
Mikel

[RichP]

Are you sure it's your ac, the PS pumps whine alot. If it only whines when the clutch engages then it is the ac, if it whines all the time it might not be. Be very careful with this, take a long handled screw driver and with the engine running plant the pointy end at different points and put the blunt end up near your ear, it will act as a stetiscope [or however you spell it] and help to locate any vibes. Just watch the moving parts or you might end up with a screwdriver permanently embedded in your head.

[ECKSJAY]

Originally posted by RichP
Are you sure it's your ac, the PS pumps whine alot. If it only whines when the clutch engages then it is the ac, if it whines all the time it might not be. Be very careful with this, take a long handled screw driver and with the engine running plant the pointy end at different points and put the blunt end up near your ear, it will act as a stetiscope [or however you spell it] and help to locate any vibes. Just watch the moving parts or you might end up with a screwdriver permanently embedded in your head.

Ummm...

[Mikel]

When I turn the AC on and off, the noise comes and goes. No need for screw drivers inbedded in my head :)
Thanks.
Mikel

[RichP]

I went out last nite to the store and rolled the windows down with the ac on and listened to it kick on and off in the driveway. I guess you could say it 'whines' a bit, you can hear it when it kicks on but with the windows rolled up the sound is almost not noticable, it almost makes the same sound when you put large aux lights or accy load on the electrical system and the alt needs to really work a bit, more of a hummm and the engine changes idle speed. I wonder if the added load of the compresser that normally free wheels when not working might be generating some noise from an idler pully or the harmonic balancer.
I don't think there is anything you can do about it, not without major AC surgery, the only relatively easy part to replace without evacuating the system might be the clutch assy provided it's not pressed on.

[Mikel]

The clicking I assume is normal, but the noise I'm describing is more of a "MMMMMMMMMMM", RPM dependent, not very different from a whining water pump. It is not bad, but I'm hoping it will not get worse.
Thanks.
Mikel

[bchulett]

It's normal.... but annoying. My XJ has been whining since new.... 150K miles now and the compressor is still good.

I'd drive it until it stops blowing cold air....


Keep screwdrivers away from ears and rotating parts.... all it takes is one mistake.

[Mikel]

Thank you all.