air conditioner how it works?

i have 97 regal gs....ac stopped working...lost freon...i bought gauge and 1 bottle of r134a...when i hooked up gauge it told me i had only about 10 lbs of freon...i used bottle to charge system through the schrader valve near the firewall after i put in about half the can i noticed that the pressure from the gauge on the low side was approx. 100 lbs....way too high! i removed the gauge and noticed there was freon leaking from schrader valve... i brought the car to the shop and explained what happened and they told me schrader valve was ng and replaced and recharged system...1 day later the ac stopped working, so i looked at valve and seen yellow dye around it...brought car back to shop and they told me new schrader valve was defective and needed to be replaced...2nd valve was put in and system was recharged and the ac stopped working 1 day later...called shop and they told me the hose was no good and needed to be replaced at an additional charge....i agreed. after i picked up car w/ new hose ac worked for 1 day...i looked at hose and seen yellow dye around schrader valve of new hose. i called shop and they told me to bring car in....later that day i got a call that my compressor had a leak and needed to be replaced. itold them i could not afford it right now and will pick up the car...when i picked up the car, before i even started it i looked under the hood to see yellow dye and lubricant all over the pullys, belts, compressor, firewall and alternater. i showed the service manager this and he said it was like this when i brought the car in. i told him it was not, since ac did not work for a week and that i checked the engine oil the day before and did not see any yellow dye on the pullys, compressor or anywhere in the engine compartment except the schrader valve on the new hose that was just replaced. he stated that the compressor was initially diagnosed as haveing a leak when it was brought in. i then asked him why the dust covers were missing from the low and high side. if a leak was first seen, then why would these covers be taken off....no need to try to charge the system if a leak was detected. leak needs to be fixed first then try to charge, right? CAN ANYONE TELL ME WHY the low pressure hose is reading 100lbs at the schrader valve and if you tried to charge the system in this condition could it damage the compressor or any other parts? Also at what point does high pressure convert to low pressure, or how is it possible to get this kind of high pressure on the low side?

The low and high side pressure should be within 30 psi of each other when things are working properly. High pressure on the low side could be a defective check valve or when there is higher than normal pressure on the low side or it reads higher than the high side it indicates a compressor problem. Sounds like your compressor is leaking severely and already damaged. I would not attempt adding any more R134a refrigerant because its way too high as it is.

If you want to DIY the AC I'd suggest getting a good service manual.




http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials

thanks bnaylor....info helps me understand more now...can you tell me where check valve is located and if the system was charged with defective check valve could this blow a seal in the compressor....meaning that the pressure of the freon was too high returning to the compressor?

also id like to diy for my a/c since i think im being screwed by the shop....i usually have no problems when i do the work myself,, i have a mechanical knowledge...i install and work on printing presses and for the most part have done all the work on my own cars for the last 20 years... the only reason i had the shop do the work was because it had an aftermarket warranty...

Bob is correct in his analysis of your situation. Unfortunately the bad news is that you have already been screwed by the shop, in that if the shrader valve was leaking and they replaced it correctly there should not have been any reason for additional trips to the shop. At the present time you will need to replace practically the entire system to get it working again. You will need a new dryer and accumulator, a new compressor and a new filter along with a new check valve. Since the compressor blew out the entire system will need to be flushed before you can put a new system on. Go the local wrecking yard and find used parts for your car. Once you have purchased what you need then I suggest you purchase an AC manual so that you can see what needs to be done to put it back in service. You won't need a new condenser or evaporator but you will certainly need practically everything else. I would, however, not try to diy this job. You will need special oil and cleaner to flush the system as well as a vacuum pump to evacuate it before recharge. Take to anoter shop that does air conditioning repairs and get their opinion.

If I were you I would file a complaint about the shop you used before because it seems like they are in the business of taking money and not repairing the problems. Any good shop would have done a complete diagnostic on the system to find out what needed to be done before wasting your time and money to do the rapairs three times and still not get it right. Good Luck!

Well put GTP Dad and I agree. His situation doesn't look good.

After the parts are replaced as suggested along with purge/flush, evacuation and recharge it will take initially 32 ounces of R134a refrigerant and 8 oz. of oil. And hopefully there will be no leaks after the work.

Good luck!



http://i5.photobucket.com/albums/y186/lizzywiz/gtp.jpg
Thrasher CAI, DHP v1.0 PCM,
3.25 SC pulley, CAIT GMAF, Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 TB,
TB spacer, MSD 8.5mm wires, Autolite 104s,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials