Failing A/C compressor clutch?

Yes, I've searched.

'99 XJ 4.0, 160k
No lift, DD, well-maintained

About 10 days ago, my engine bay suddenly had a new sound - not a good one, but essentially a "dry" metallic sound, that I think is coming from the A/C compressor and its clutch (Sanden 4722/709T). The sound is constant at idle but not a squeal like for a slipping belt, and I dont notice it at speed. It's winter here, and my defroster stays on when I'm driving, thus using the A/C - but when I tested just the A/C alone, it seems to blow appropriately cold, though it did sound like the belt (which is new) slipped and squealed a bit at first.

So is the clutch on the compressor failing? I don't notice any leaks from the compressor, didnt have the pulley checked when the belt was recently off, and the in-cabin A/C seems normal.

And do most of you guys rec changing the whole compressor instead of just the clutch? The whole unit is original to the Jeep, and everything else is well-maintained.

Thanks again, in advance -

David

Noise when NOT using the A/C, but it goes away when you are using it, is that right?

If that's the case, the bearing in the pulley is bad or going. I'll leave it to the other minds on here to determine if you can just replace the pulley or if you have to do the whole compressor...

--Andy

It is probably the free-wheel bearing going. Probably easier to replace the whole compressor. It went on my '96 two years ago, and my system was not charged at the time, so I just replaced it with a very low-mileage piece I found at the JY...Thank you, C4C! I tried to pull apart the old one, but it seems the clutch assembly is one piece with the inside of the compressor, probably needing special tools to disassemble it, if it's possible. I ended up with the pistons coming out, so I gave up on it, and just swapped in the replacement. If your system still works, you should have a shop evacuate the system, just so not to spew the refrigerant. I purchased the bypass pulley, but it's for a ZJ, and not a direct swap. But, I could make it work if I had to.

Keep in mind that when the bearing does fail, your jeep will not be drivable unless you have a shorter drive belt sitting around to bypass the AC compressor. I will echo the earlier comment that you should just replace the whole compressor rather than trying to find a replacement bearing.

When the bearing on my compressor failed a few years back I had no choice at the time but to tow it to the dealership and have them replace it for a cool $750

Replace the whole compressor. I've taken apart one that had a seized pulley. It is NOT easy.

Sounds like a bad bearing.

Replace the pulley assembly from a 95 and earlier unit from the JY. Those are rebuildable. No need to do anything with the AC system as a whole.
The Clutch is not part of the compressor per se. There is one nut on the clutch plate, a few flex washers under that (don't loose them), a circle clip on the bearing/pulley assembly.

Until then, to prevent a total failure, you could get a bypass pulley. Unbolt the compressor and wire it to the side. Install bypass pulley ( you will need to lie about the year of your Jeep in order to get the right one )

I would rather spend 5$ for a used, but serviceable part at the JY than buy a new compressor and the legal* removal/installation of the Freon/R12 by a garage. Still, it's a skill level thing.

Just had this done on my 96 Bearing got so bad there was brown "dust" on rad hose and bottom of hood.
Clutch alone was$250,whole new compressor was $299/w/clutch...a no brainer.

Thanks for the responses, and I think I agree with the advice to replace the entire unit: clutch AND compressor. I have to assume that if the clutch is failing, the internals of the compressor are affected somehow, and may even be failing on the same schedule.

I am still driving the Jeep daily, but am not using the AC at all (for defrosting or actual AC) - but will that save me time? I don't hear the death squeal unless I turn on the AC, but is the pulley being engaged, spinning the clutch during normal operation, killing it? I dont want to get stranded - and I'm ordering a new unit today.

If it's the freewheel bearing, then I have to disagree with replacing the whole compressor. Take the belt loose and see if the compressor pulley has a lot of play in it. You can get the bearing from Auto Zone for about $20 and rent the pulley puller and installer there too. You don't even have to disconnect the refrigerant lines to change that bearing.

I'm having the same issue and looking for a bypass pulley but can't find one. I have a 2000. Where can I find one?

The 2000's compressor mounts with vertical bolts.
I don't remember which year's mount the Sandens this fashion, but the parts listing will have two types, one that mounts to a flat plate ( bolts down ), and one that bolts though the front (bolts horizontal).

I'll see if I can't locate a P/N

Edit:
This should do it P/N BK 6601928
http://www.napaonline.com/Catalog/C...8004+4038007+5999999+30508&Ar=AND(P_RecType:A)

Thanks for all the comments; I wound up replacing the whole unit (clutch and compressor), and am very pleased with the results. It's totally quiet now, the AC blasts colder than I've ever felt it, and my mind is eased....

FYI, when we removed the clutch, which wasn't spinning freely at all off-belt, the compressor showed serious signs of decay - so I'm glad I replaced it all together.