A/C Help

Birdie2000

Birdie2000

Club Member
The car is a 1999 Jeep Cherokee 4.0. Blows hot air. Had a can of refrigerant around so I hooked it up, pressure was a little low but not much. Topped it off, still blows hot air. What else could it be?

The only other relevant thing that happens sometimes is if you turn the fan on to settings 3 or 4, it'll blow like normal for about 30 seconds, then you'll hear like a flap closing and it won't blow out of anywhere. Thought this might be a separate issue, but is it possible that for some reason the flap covering the heat exchanger ducting isn't closing properly and thus not letting the cold air come out of the vents?
 
Birdie2000 said:
The car is a 1999 Jeep Cherokee 4.0. Blows hot air. Had a can of refrigerant around so I hooked it up, pressure was a little low but not much. Topped it off, still blows hot air. What else could it be?

The only other relevant thing that happens sometimes is if you turn the fan on to settings 3 or 4, it'll blow like normal for about 30 seconds, then you'll hear like a flap closing and it won't blow out of anywhere. Thought this might be a separate issue, but is it possible that for some reason the flap covering the heat exchanger ducting isn't closing properly and thus not letting the cold air come out of the vents?
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Or that same thing that controls the flap isnt switching from the heater core over to the condensor.
 
definately sounds like a blend door issue

agreed, is the compressor turning on? are you able to check high and low side pressures? any of the lines under the hood getting cold?
 
if your using one of those cans with the green blue and another color scale then you have to be in the proper area with the compressor actually engaged. if its in "the green" statically then its actually too low and won't cycle the compressor
 
The compressor is kicking on. The pressure will drop out of the green range when it comes on. It only cycles for a very brief time though, maybe 5-10 seconds. After that the pressure returns to normal. I have no way of checking the high pressure side. Like I say, even with the heat, when the fan is on the high settings, you'll hear what sounds like the flapper moving and then the airflow doesn't come out of the vents any more. I'm pretty sure it doesn't come out of anything at that point, but don't know for sure as it's my gf's car and I'm not in it much. I didn't think to grab the lines and see if they were getting cold, I'll check that next.
 
You will not get it to cool properly just by adding refrigerant. You have to have the system drawn into a vaccuum & then properly charged. You need some a/c equipment to do this.
 
dave89iroc said:
its still low, add more refrigerant, it should be in the green with the compressor running
Click to expand...

Ok, at idle it's high, almost out of the safe range, didn't want to overfill it. It only turns on for like 5-10 seconds at a time, so when that comes on and the needle drops, it needs to still be in the green when it drops? What if it's in the unsafe region when the A/C is turned on but the pump's not compressing?

I'm trying to do this on the cheap for her, not really in the position to spend all the $$$ that A/C service requires if we don't need to. Cans have worked for me in the past...
 
I have an outpatient procedure tomorrow morning, so depending how I feel I'll let you know if I can. I really appreciate the offer!
 
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