92 Camaro

iTrader: (1)

My ac just stopped working the other day. I thought it was the blower motor because it used to make noises and and then just did again before my a/c stopped working so I replaced it with a brand new one. Well, that didn't fix it. What's happening is when I slide the ac to anything, it wont turn on (just my fan). I checked the pressure and it was at like 110 psi! It was never that high. Last time I checked it, it was at around 45. So I let out all the AIR inside of it. Just a small squirt of refrigerant came out. I did this until no more air came out. A/C turned on. Very warm, but it turned on.
I took a can of refrigerant and tried filling it, but as soon as I pushed the button, the gauge was showing it in red ( 100+ psi) and when I let off the button, in yellow (50 or so). Trying to release the refrigerant and air again didn't work.
A guy told me it's got a leak where it sucks air??

GICATA

Well A/C is like electrical systems....you don't want to let anything out. By pushing the valve, you discharged all the refrigerant. The gas blew out and drug a little oil with it, that was the "A/C" you saw at the end.
If the pres. was 110 with the system off/not running, I might say that was okay. When AC is idle it balances the high and low sides. When on (compressor turning) the two sides should be as follows: low (blue) 35 + or - a few pounds and high (red) should be around 140. High sides can/will vary as can low but those are in the range.
If the AC won't cool eventhough the fan blows there can be any of several things wrong. Pressure or charge is normally the problem, usually caused by leaks in any of the seals, joints or components. A full charge with leak dye and careful inspection with a special light will locate the leak.
If there is no leak, then a component failure is the next most likely. Orifice tubes, expansion valves, or a plugged evaporator or condenser could be the culprit. You can sometimes find an "un-normal" temperature variation in the cond. or evap from a plug.
There could also be a problem with a relay or pressure switch....or the diode in the connector at the compressor.
To get the air out you must evacuate the system with a pump for 20 minutes or so. This removes the air and moisture from the system that otherwise will compound anyother problem it may have.

So you see AC diagnosis can be involved and should be checked by a trained technician with the right tools. There is no way to tell now what was wrong with yours without the proper charge and diag.

92 Camaro

iTrader: (1)

ok so of course it's time to have a shop take over. but why would my pressure get so high? the system was not running when it read 110. it read that before I pushed the pin (everything off) and while I was putting in refrigerant.

GICATA

Because when the system is off/idle, it balances the high and low pressure to neutral in the system.
While in operation it may have 35 on low and 250 on high pressure sides, when off those pressures equalize to a median pressure...say 110. It is normal for this to occur.

http://www.familycar.com/ac1.htm

http://www.automedia.com/How_Air_Con...cr20020501ah/1

camarosrock1989

iTrader: (1)

Ok I hope someone can help me figure this out, sorry 92camaro for jumping on your post. I have R-12 in my ac, here is what i thought the problem was, the connector on top of the compressor was kinda fried. So I replaced that, was not the problem. The AC has worked, some days it does but most days it don't. I can feel cool air at the vents but not blowing. So is there something that makes the blower work? I live in Az and its hotter than H*** and I have a black top. Was thinking about just replacing the compressor, but if mine is not bad i would rather spend money on something else. Please help me figure this out. Thanks Guys

92 Camaro

iTrader: (1)

i forgot to reply to this thread, but only got it fixed recently. the switch behind the unit was fried. new one allowed everything to work except max, which would come out all vents except the main ones. So, I got a used one.
sounds like your blower motor is DEAD. check the voltage coming out of it with the ac on.

camarosrock1989

iTrader: (1)

That is my next step, fan motor. I sure hope this fixes it! Thanks

RS-Chevy-SS

Yeah if it was making funny noises then I would change that. Its only like $40 if I recall. Pain in the *** though with the lower bolt if I recall

camarosrock1989

iTrader: (1)

Changed the fan motor today, I have AC, works great!
Thanks for all your help! Next fix is my contact plate for rear spoiler brake light.

92 Camaro

iTrader: (1)

glad I could help.

Reid Fleming

iTrader: (2)

Air conditioning systems need to be vacuumed down before putting in refrigerant. If you "let all the air out" of the system, then it's now full of air. Air is very hard to compress. Thus you get the sky high pressure readings.

A shop would put the system under vacuum for at least 30 minutes. Thus sucking all the air and pressure out of the system (pressure would be below 0 psi on the low side) and then put refrigerant in.

92 Camaro

iTrader: (1)

wait, how's it get full of air if I let it out?