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A/C questions

Jbh97009

NAXJA Forum User
Location
Damascus, Oregon
I know little to nothing about air conditioning, so I'm hoping you guys can help!

My 98 has always been ice cold and all functions hvac wise work. However I noticed yesterday after about 2 hours my ac was no longer cold! :doh:

So I turned it off, and rolled the windows down and about 45min to 1 hour later I tried it again and it was cold again till I got home. Never had this happen before...

My fear is its a compressor issue, however I'm hoping it may just need a re charge. I just hate taking it into a shop and wasting $100's of dollars on a simple fix!

Any input?

Also may be helpful to note that the Xj currently has just under 230k miles
 
I also have a 98 and have had AC issues. Your refrigerant is R134a and should never be exposed to the open air as it is hazardous to the atmosphere. When you select AC the compressor clutch should energize and engage the compressor which directs Freon through the system from the high pressure side to the low pressure side. As Freon moves through the evaporator (in the cabin under the dash) it removes the heat from the air which results in lower interior ambient temperatures. You should have a high pressure and low pressure cutoff switch to prevent over/under pressuring the system. You could take it to an AC shop and perform a proper service by removing the Freon and pulling a vacuum for 15-30 minutes to ensure all contaminants are out of the system. Then the system will be injected with compressor oil (very important) and new Freon will be added to the factory specs. In a typical system, you should not have to do this often, but on our older XJ's you may have an o-ring or Schrader leak somewhere in the system (fittings) which has let out some Freon eventually leading to the high or low pressure switches cutting power to the compressor clutch to save the reed valves in the compressor.

What I think is more likely however is the problem I had. I had partial engagement of my compressor clutch and like you mentioned, it would stop working randomly after working for a period of time. Some days it would work for an hour, other days a few minutes before cutting out. Most places will tell you the compressor clutch is not serviceable or replaceable but it is. You can remove the AC clutch with basic hand tools without evacuating the Freon. When I did this, I found rust contamination on the back of the magnet that is energized when powered by the AC circuit. When the compressor got hot, the clutch could no longer hold due to the rust contamination. I cleaned the back of the clutch carefully and checked my compressor clutch gap. A search will yield how to do this as many have had to remove or add a shim to achieve the proper gap. After doing this, I have had flawless AC performance for 2 years now and it cost me nothing and took 20 minutes.

Good luck and keep us posted.
 
That sounds encouraging! I'll have to look into it.

I have wondered if maybe it needed a service like you said, but it's worked so well (up until yesterday) that I haven't bothered.

I just don't trust many shops, especially with ac because they always say 'you need a new compressor'
 
When this happens, I would pull off and pop the hood. Determine if the compressor is engaged and if the lines are iced up. If the compressor is not engaging, you could try a test light to see if the clutch is energized. If so, I would try re-shimming the clutch plate as described because its free. I had to do that on my 01 XJ a bunch of years ago. If that doesn't solve it, you could have other problems. Could be a failed low or high pressure switch so the clutch is not engaging. Like much on the Jeep, the systems are pretty simple.
 
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