AC PROBLEMS

[JAMES ADKINS]

Hey guy's it's our favorite time of the year again. My AC worked fine last year but now it's not. I'm thinking by the readings i'm getting on my gauges that it has a restriction if not complete blockage. It has a new reciever dryer and was vacummed down good before recharged last year so now i think it's either some sort of contamination or a expansion valve. The question is if it turns out to be the valve has anyone ever changed one ? The cars a 82 rabbit 1.6na. Thanks

[82vdub]

now i think it's either some sort of contamination or a expansion valve.

I'm not trained on AC systems (or anything else car-wise for that matter ), but can you tell if there's still freon in the system from the gauges? Or, is it possible that most of the freon has escaped from the system causing excessive gauge readings? It could be something as you list, or simply a very slow leak from last year that resulted in the freon loss in the last 6 months. There are o-rings in a lot of fittings in the AC system and they can crack from age. Been there done that. Can you evacuate the system to see if you have the full amount of freon in the system that it should have? If my memory serves me correctly, my 82 Rabbit takes 2.2lbs of R12 freon for a full charge.

[sideburns]

hey im more used to ac systems on heavy equipment than cars, but what are your guages reading? does this system have a high and low pressure switch that could be faulty? will the clutch kick in if you run power and ground to it direct? if so does the air turn cold then? just what i usually do to check on a system I dont know anything about...
Im guessing that from your post your compressor is turning on, but no cold air?

[JAMES ADKINS]

Yes the system will run on the switch but only after i get some charge in it, to do that i have to bypass switch tempoarily. The radiator fans working as well as the blower in car is on full. Now heres the wierd part., this unit was evacuated last year and recharged and performred very well. Ok now this year i get extremely low, low pressure readings and high, high pressure readings +5 and 300+ on low and high side and the tube going to condensor will get extremely hot. Soo i reevacuate the system this season and install a new reciever dryer along with a 4oz. can of pag oil and no difference. From my experiance this usually indicates a stopped up or restriction somewhwere. I used to install units in heavy equipment and i am MAC certified and the last time i had one act this way it was oil slogged. Thats the problem when you repair someone elses broken stuff after it becomes yours, you just have no idea whats been done so your guessing. Sorry for the long reply but i',m now thinking a good flush out is in order.

[bscutt]

Sounds like a clogged expansion valve or somewhere in the high pressure line before that valve? I have to go back to my AC system diagrams to see if that makes sense but that's my initial thought.

[JAMES ADKINS]

My thoughts also, thats why i asked if anyones ever changed a expansion vave on one of those things? I sure hope you don't have to tear the car apart as i suspect that will spell the end of that AC unit if it does.Thanks to all.

[82vdub]

i reevacuate the system this season and install a new reciever dryer along with a 4oz. can of pag oil

i am MAC certified and the last time i had one act this way it was oil slogged

Possible by adding the oil that it does have too much oil in it? Or when you change the dryer, does most of the oil come out with the dryer?

[JAMES ADKINS]

Yes i'm very suspiscious that it may be oil slogged. If i were to really do it up right i would remove compressor and drain it, then add 5 oz. of pag purge all items and check for flow with compressed air afterwards.Finish up with fresh reciever/dryer evac and recharge & hope the expansion valves ok. Let me know what you think and as always Thanks.

[Caerbannog]

By coincidence, I'm working on the AC on my '82 NA now. On my Rabbit, the expansion valve is external to the heater/AC box, on the right side of the heater box, You get a pretty good shot at it if you were to remove the glovebox.

New expansion valves are available for a reasonable price (don't recall exactly, but not outrageous) from the local parts place or perhaps from Jack.

Hope this helps.

[JAMES ADKINS]

Cool that's what i was hoping tto find out.

[JAMES ADKINS]

Have flushed system out and removed exp. valve. The valve had alot of debris in the feed end of it. I'm sure with that tiny screen in there that that was the prob. I have a new one coming and hopefully all will be well now. Will post back after finishing. Oh BTW the debris did'nt look like amything out of the compressor, it just looked like gook. Later dudes.

[JAMES ADKINS]

Well she's fine now. That thing throws cold enough air now to make you shiver. The main root cause was debris blocking the screen thats in the exp. valve. I do however have one problem, when i diconected my alt wire it shorted momentarily and has opened a link somewhere. No fuses blown but it is now dead so i've got that to repair and then hopefully all will be fine. The wire that shorted was the d+ signal to dash indicator wire.

[JAMES ADKINS]

ALL probs repaired now. The ac works far better than last year. I suspect it was partially stopped up then.