My AC starts out cold. then after about 15 minutes the air warms up, as if the AC unit isn't working. Then it will start working again.

Any ideas on what to start looking at first?

 

There's a video on YouTube but I'll explain quickly as this happened to me. This is only a "temporary fix" because the clutch will eventuality stop working.

You need to remove the compressor clutch pulley. There is a thin shim you can remove then put the pulley back on.

I did this about two years ago and it's still working. Your results may vary.

 

You might want to check your refrigerant pressures as well.

If the fan-clutch is going bad it may be seizing or something after it gets hot, causing the compressor to disengage.

One option is to jumper the low-pressure sensor and see if the compressor kicks on. if so, its probably low refrigerant pressure.

If the compressor still doesn't come on, its probably the unit itself (either replace the compressor or you can try to shim/un-shim the clutch to get some more life out of it).

 

^^


The OP has a 2001. It's not as simple as the earlier XJ's when it comes to jumping switches.


Here's some data that pertains to 2000/2001 XJ AC systems:

 

mine still working after 2 or 3 years after removing shim

 

Well, a quick recharge seems to have done the trick..... We'll see......

 

Well keep an eye on it and fingers crossed - if it leaks down it's pretty likely the evaporator which is a royal PITA to change out on an XJ. (The dashboard has to come out of the vehicle!) I'm probably going to have to do that job on mine, it's losing refrigerant and my electronic sniffer unfortunately can't find a thing leaking under the hood. Not sure when I'll have time for that project.

BTW, do not be tempted to use an AC sealer! Those products are snake oil of the worst kind. They likely will not work and will likely destroy your AC system. Sealers can also damage any equipment hooked up to your air conditioner such as a gauge set or a shop's expensive refrigerant recovery gear. You don't have to take my word for it, check out this forum where pro AC techs hang out, searched for "sealer":

http://acsource.net/acforum/search.php?keywords=sealer

 

Any chance of posting the YouTube link. ?