My 2000 XJ started to blow warm air yesterday. I had Evaporator, condenser, dryer, lines, Denso compressor installed 5 years ago. Not sure what the problem might be. The compressor cycles are short and fast. I checked for obvious leaks but I could not find anything. Could someone assist in diagnosing a potential issue. Thank you in advance.

video:

 

I have been trying to fix the AC in my '00 for 6 years now.
I try one thing every year. I really don't care about AC. LOL.
What I think I am seeing is at the very least you are low on refrigerant.
Thinking at about 77 degrees should be about 35 to 40 on the low side and about 150 to 170 on the high side.
When the compressor kicks on.
You want to be sure when checking though that the Jeep is hot to the point of the Aux fan kicking on.
Also want the RPM to be about 1000 according to my '01 FSM.
I have watched a bunch of videos about AC. Still don't know squat but am learning.
One video I watched the guy put a box fan in front of the car to blow at the condenser.
I could not figure out why. Seemed stupid. I run a test and my high side is reading really high.
If I remember correctly. Well from idling out there the fan finally kicks on and all of a sudden it drops.
To more along to what it should be. Then it dawns why the box fan.
So if that were me I would add more refrigerant with dye and maybe determine if and where I have a leak.
Of course none of that has helped me. Thinking I have a very small leak in my Evap Core.

 

If it is low on refrigerant, inject some with UV dye in and look for leaks.

 

Not sure if this is normal. But yesterday when I took out the high side connector the schrader valve leaked. I thought this was the culprit but this morning I sprayed soapy water and no bubbles. Not sure if this is normal after taking the connectors off. I was ready to buy the tool to replace them under pressure. Any thoughts ?

 

When you say took out the high side connector do you mean removed the protective cap?
I can see you maybe not having enough refrigerant left in there to see with the soapy water trick.
Maybe it is not tight. Maybe it needs to be replaced.

 

I would think it is more likely that the leak at the Schrader valve was temporary, created by some bit of contaminant that got under the seat when you operated it, with the spring pressure eventually crushing the offending bit enough to seal.

 

Ralph77 posted while I was typing mine. He makes a good point that refrigerant pressure could have leaked down enough between your two leak tests that the second test was negative. Assuming refrigerant is low anyway, you could try charging with gas containing the UV dye, check the Schrader valve first, and then continue the search if necessary. Hardest one I've had to diagnose turned out to be a pinhole leak in the core under the dash.

 

If your low side temp is accurate, 24 degrees, then you are low on refrigerant. You need to add until you get to at least 34 degrees. What is happening is you are freezing the coil and it has to thaw before it will cool air again

 

I got the UV Dye today and I have a few bottles of R-134, I'm now waiting for the schrader tool kit to show up tomorrow.

Thanks again for the comments.

 

UV DYE is not visible. What's the overall feeling on using R134 with stop leak? I never used one before and now it seem that most outlets sell R134 with stop leak. Thanks in advance.

 

Never heard anybody who does AC recommend that stuff, quite the opposite. My intuition is that it is a bad thing to introduce to an AC system too.

If you injected dye and are still not finding any leaks, sounds like that intermittent valve leak you heard is the likely culprit, until something else is discovered.

 

puredrive,

I just watched your video. That is classic symptoms of being low on freon. You still have enough to allow the system to cycle, but not enough to run.

you can mess with the dye, etc. but after 5 years I would bet you have a very slow leak that will require topping off the system on occasion.

I Service a few a year because of that. I put a can or two a year in depending on the size of the system.

$5-$10 and 15 minutes. Unless it gets where it leaks out fast, I don't try to find the tiny leaks.

Dont use stop leak in a ac system. There are to many tiny passages that can be clogged.

you need a black light for the uv dye

good luck,
Joe W

 

Another possibility is to use an electronic refrigerant detector to find the leak. Mine goes crazy inside the Jeep after running the AC so I know I have an evaporator leak. (A project for spring if I can find the time. A bit of a daunting job.)

 

Quick update. I used a R-134 can with dye to fill up. I did maybe 1/2 can and the system cooled down to 47F inside the cabin. Temp was around 60F ambient. System seemed fine and the gauge was within the parameter per chart .

Later in the afternoon , I ran the system again, ambient temperature was 72F. Problem that I saw right away was the low side not moving at all and the couch was engaged for much longer then usual.

Took a short video
https://www.youtube.com/watch?v=STLh...ature=youtu.be


Rambler65 do you have a suggestion on a good value unit ? I still can't find a leak. Would not mind trying this option.

 

I know this is going to sound stupid but did you tap the gauge with your finger?