A/C question

[jay79cj7]

00 XJ, 4.0L... The past few days when I have started it up cold, sometimes the belt has squealed for the first 30 sec or so, then stops. It sounded exactly like when I changed it and had it a little too loose, so I was going to look at it this weekend. Today I turned the AC on. I haven't run it much in several months, but have used the defrost. It seemed to not be working too good at first, then started working fine. 20 min later I realized I was getting hot, and the AC was not working at all. There was no difference between AC and vent at all. It stayed this way for the rest of my hour drive through bad traffic. I popped the hood and all the AC lines were warm, where usually you would have one warm, one cold. So I figured great, the compressor is shot, or I have some wiring problem so its not turning on. Well, when I went to go home a couple hours later, I started it up cold and it squealed. I turned it from AC to vent and the squeal stopped. Turned it back and forth and the squeal went on and off for a little bit, and then the squeal went away like normal. The AC worked the whole way home, a 45 min drive this time. What gives? Why would it not work at all, then start working again? I haven't had time to screw around with it yet, and will tomorrow, but I am confused here, and not sure where to look. Is the clutch going bad?

 

[White]

wirring possable, Faulty Pressure Switch. Was the outside air temp higher when it started to work?
you could jumper the pressure switch out and check the superheat. Or Subcooling if it has a txv ( Most likely) Excessive Superheat means Low Charge.
As for the squeel, Tighten it up more .. Maybe the pulleys are polished from a loose belt. Or try some of that belt dressing.
Before meally messing something up You might want to take it to a Professional...



I can't spell..

 

[jay79cj7]

It was actually about 20 degrees cooler when it started working. I was thinking maybe the clutch is going bad since it squealed only when the AC was on (clutch engaged). I have a buddy that is a Land Rover tech. I guess I will have to have him take a look.

 

[jay79cj7]

I think its just low on R134a. If it cuts out and I turn it off for a while, it comes back on. I bought a 15 buck filler hose with pressure gauge. It was low on pressure so I put a can in. We will see how it goes, but its cooled off again here, so I don't know if I will figure it out for a while. I think thats all it is though because I reved the engine a few times while filling it and the higher rpms made the compresser work faster, thus making the input line lower pressure. When the pressure dipped, the clutch let off. So I think it just was being over worked for the charge that it had in it and the system shut off because of it. I am keeping my fingers crossed.

 

[White]

Ya, you can go round and round on here with it... But if it did loose charge, Where did it go. Might want to find that leak.

All compressers leak from the shaft seals. But not that fast.
Maybe a hose or Condenser/Evap. Find someone with a Electrinic leak detector.

 

[jay79cj7]

This is what I am wondering as well. Its leaking somewhere I guess. Some leak is normal, and I don't use the A/C too much, so I am hoping it has lost its charge over the past year and I just haven't found it until now. If that is the case, I can live with adding a can or two every summer. If its a bigger leak than that, then I will have to do something more serious. Any idea if that stop leak stuff works at all?

 

[XJNick]

Any idea if that stop leak stuff works at all?

Hi,

I've been told to NEVER use this stuff. Like it says, it will stop your leak... and the rest of the A/C system. I can't imagine that using this in a system which has many small orifices could be good anyways :?

-Nick :!:

 

[White]

Agree with nick!

 

[MudderChuck]

I´ve had pretty good luck, chasing down leaks, by checking all of the joints and hose connections for an oil stain. Refrigerant is mixed with oil and even a small leak, over a period of time, will leave a small stain that often attracts dust and can be seen. Then with the system off, a little dish washing soap mixed with water and a small brush to paint the joint, will show small bubbles. A very small leak requires some patience, one small bubble may pop up every thirty seconds or so.
If the leak is in the evaporator or at the compressor seal, it will be harder to find and fix.

 

[whiterubicon]

Have it checked for a leak. If it has one then just get it fixed if you like your air. By not getting it fixed and just adding freon every summer is just going to harm your system. Once moisture gets in the system then it will start to damage the whole system. That includes the compresser, dryer, evaporater, condenser, switches, everything. Then it will not be cheap to fix. Most leaks are caused by o-rings. They are the least expensive thing to replace.

 

[jay79cj7]

OK, thanks for the advice guys. It hasn't been warm the past few days so the system really hasn't been challenged. I did check the pressure a day after adding the can and it was the same, so its not a big leak, if a leak at all. I understand that all of these systems lose refrigerant over time, so maybe I lost 1 can over 4 years. If so, no big deal. I will keep my eye on it and if it gets low again any time soon, I will get it checked out. I actually bought a spare can just in case I need to fill it up again, and I got a kind for "high mileage vehicles" with lubricant and some stop leak. I will return that for sure now. Thanks again.