Hi,

The A/C is acting up on my 01 XJ Sport.

Findings:

1. At 65F ambient temperature and the vehicle off, manifold gauges indicate pressure around 60 psi.

2. When I turn on the A/C, the compressor cycles normally for a few minutes, low pressure cut out is around 20-25 psi and cut on is around 35-40. High side is around 100-150 psi. Dash vents blow around 42-44F.

3. After a few minutes, cycling stops, compressor remains engaged, low pressure is 35-40 and high pressure is around 200 and both slowly rise over time. Dash vent temp increases.

4. Driving around for some errands, I put the A/C on a few minutes from home. When I pulled into the garage I put manifold gauges on it. Same condition as #3, except I was able to see much higher pressures. When the high side gets to 325-350 the fan comes on and pulls it down quickly. However, low side only drops from about to 50 to 40-45.

Is this indicative of a restriction in the lines, such as a faulty orifice tube in the liquid line? Or that my compression just doesn't work once its "warmed up" ? Looking for some additional input before I spend money on replacing the line, compressor, or recharging.

Thanks!

 

By no means am I an AC tech, but I think I would make sure the freon is actually flowing like it should when at full operating temp.

Your system can actually have too much freon in it, which would cause some of the same problems.

 

How do you check flow? I charged the system with 1.25 lb R-134a.

 

I have an 01 and just did my ac this past weekend. You may have put too much R134a in the system. It is designed to hold a max of 1.25 lbs. So, if you added 1.25 to what was already in there then you are overcharged. Don't run the ac until you resolve this. Here is what I posted in another thread.

To start with, my buddy is a master technician and already owns all the proper tools and possesses the proper knowledge necessary to service an ac system. We did my XJ at his house this morning. My ac didn't feel as cold as last summer (still cold though) and the compressor seemed to cycle more.

We started by carefully checking the entire system for leaks. None were found.

Then we hooked an ac vacuum pump to the system to evacuate any air or moisture that got trapped in the system. The vacuum procedure took about an hour. I had accumulated a fair amount of moisture and air in there. IMO, If this part of the procedure is passed over it can possibly lead to a premature failure of the compressor and you can't achieve max cooling from the ac.

After the vacuum procedure, engine running, and the ac on max with highest fan setting we began to add refrigerant very slowly while monitoring hi/lo gauges. Once we got the readings he wanted, we checked the temp inside and it was unbelievably cold.

240 high side
38 Low side
85 Degrees Outside
Engine at full operating temperature

Checked system again for possible leaks. Again, none found.

I drove the XJ home with the ac fan set to the lowest position "1" and that was plenty to keep me cold. Outside temp was 85, high humidity, and the sun was bearing down on the Cherokee. It's now ready for the 100+ summer temps in N. Texas.

If you don't have the tools and knowledge or a friend that does, I think you'd be better off to have the service done at a shop.
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Hopefully this will help point you in the right direction to get your ac working correctly again.

 

Thanks, but unfortunately this does not help because I vacuumed out the system and put in 1.25 lbs of R-134a.

 

You might have to wait till it gets to be around 80 degrees or so to really check the system out.

I have had AC techs tell me 65 is not high enough to get an accurate picture of what is going on.