Yarrik

Background:

I have a 2000 XJ Sport with a serpentine belt that would sequel when I would first turn on the AC and then go away. The AC would still function fine and was plenty cold.

The belt broke the other day. At first I thought it was just a worn belt. After replacing it, I couldn't get the sequel to go away. I was incorrectly thinking I didn't have the belt tight enough. After I tightened it as much as I could, it still wouldn't stop squealing - nor would it turn all the pulley's very fast. I took off the belt and checked all the pulleys. I cannot manually turn the AC pulley by hand. The belt will barely turn it.

My theory is the AC unit froze, which caused enough tension/friction on the old belt to break it.

My questions:
How do I determine if it is just the clutch on the AC unit? If I replace the unit, other than recharging the unit, do I need to replace anything else? I have read others mentioning a dryer/evaporator that should be replaced as well. Is this correct? What other issues should I keep in mind if I attempt to do this procedure myself?

Thanks for any info/insight about this.

Tige

headRUSH

The unit itself should be really easy to replace. I don't know how to diagnose A/C but I will tell you this: when/if you take it off, whack each bolt really hard with a hammer before taking out, and use plenty of WD40. It's aluminum, and really likes to corrode the bolts in the holes.

Pelican

What "unit" Are you asking about replacing just the clutch or the whole compressor?

I am sure you will get some answers but in the meantime a quick search will find threads on this subject over the past several weeks.

You must replace the drier to maintain the warranty on a new compressor. Replacing the evaporator (under dash part that cools the warm air) is a major PITA and not required unless it is leaking.

md21722

You should be able to rotate the clutch plate by hand. This is directly connected to the compressor shaft. Unless the clutch had seized on.

As old as both and the cost of a new compressor vs only the clutch, I would replace the entire compressor assembly. These are $200-250 at Auto Zone etc. Accumulator and liquid line should also be changed with compressor. Another $60-70.

Ditto on the compressor bolts seizing up in the aluminum mount. Hammer sounds good. I had one freeze up on me even with plenty of penetrant and walking it back and forth. Had to retap the threads.

Yarrik

Finally got around to getting back to this and getting it fixed.

Question - what type of oil do I need for the a/c compressor?

Thanks for all the help and insightful info from everyone here.

Tige

Bustedback

PAG R134a oil. Follow the instructions to a T that came with the compressor.

Yarrik

That's actually the problem - no instructions in the box with the new compressor.

I consulted Google and found this recommendation. Note at the top is says Murray recommends Ester Oil 100 weight for all of their compressors. The new compressor I purchased is a Murray SD-709.

Do you have conflicting info?

Tige

Bustedback

You can use either oil, just use what the compressor manufacturer recommends. I have always used PAG with no problems.

Yarrik

Thanks to everyone for answering my basic and silly questions.

I got the Dryer and A/C Compressor installed today without much issue at all. I was correct that the clutch on the existing A/C Compressor was frozen and unable to turn. The good news is the system was holding refrigerant quite well.

Tige

djb383

Don't forget to replace the liquid line (post #4)....it contains the orifice tube which is another filter and costs about $35.

Ooops, probably too late.

RTorrez1

What ever you do, Do Not just try to fill with freon when you get it all together. Take it to an ac shop and have them pull a vacuum on the system. If you don't do this you will be replacing the compressor again real soon. You need to get the air and moister out of the system before refilling.

extrashaky

You can also find a 25% off coupon for Harbor Freight and use it for a vacuum pump and a set of gauges. You'll spend the same or slightly more than you'll pay for the A/C service at a repair shop, but then you'll have them for the next time you need to do A/C work.

Artor

2000 Jeep Cherokee Sport
We are having issues with our AC. 1) It stops cooling after a few minutes, 5 at the most. 2) The whole thing would turn off on its own, air and all.

Checked freon lvl with one of those recharge kits from the store. when AC is off the gauge reds RED, or warning. When AC is on it drops back down to BLUE, or filled. I read in another forum that it meant that my lvl was too low and I had to fill til the gauge moves on its own back up. the needle would be half way in the blue so we topped off the rest in blue. didn't go any higher. Is this normal? high lvl when off and drops to normal when on?

At the moment we have no idea why the whole thing would shut off randomly. but one thing at a time I guess. Please help.

kgm

There is a guy on ebay who sells clutch rebuild kits FYI. It's the front clutch plate, the electromagnetic coil, and the bearing for the pulley wheel. It costs $85 and did the job for me. I was getting noise when the AC was OFF, not on. Charged the freon (it was low a bit, 30psi lowside not 40) and replaced those bits. Works great again! Had to splice in the coil which was totally trashed!