1998 Lumina LTZ A/C problem

[holly54]

A/C isn't as cold as it should be. Tried charging the a/c with R134 a. Pressure on gauge read as in the danger/red zone. I can definately hear the compressor kicking in when I turn the a/c on. It has always worked fine until now. I'm wondering if the temp hot/cold dial(?) in the center of the dash might have crapped the bed. If so how bad is it to replace? Any other ideas are welcome. Gotta keep the wife and kids happy

[maxwedge]

You cannot just charge system without knowing exactly what is needed to fill it, the pressure should be checked, the system evacuated and charged then a proper determination of the issue can be ascertained. It may now be overcharged hence the " red zone"

[SUPERDAVE22]

a/c will also not work right if it is overcharged, you may also have something clogged up in the system is the compressor kicking on and off and not cycling very long? if so this usually means it is clogged or the pressure switch is bad.

[holly54]

Thanks for the input. Clog sounds likely. I never added any r134a but was about to when I read the gauge and I still get hot air from the vents when I turn the temp up. How bad do you think will this hurt the ol' wallet?

[holly54]

forgot to add compressor is cycling. Pretty much turns on then off right away.

[maxwedge]

Usually that is charge issue but the proper procedure is the same.

[j cAT]

Originally Posted by holly54

forgot to add compressor is cycling. Pretty much turns on then off right away.

high pressures on the low charge port and the compressor is cycling may mean a bad low pressure cut out switch...

when the compressor stops running the pressure will rise to over 120psi on a hot day...then when the compressor starts the pressure should be 40-50psi no higher....on a very hot day close to 50,,on a cooler day 35-40psi...

with a jumper wire and pressure guage installed short out the switch so that the compressor continues to run and see if the pressure stays in the above 20psi area....if so the swich is defective...


if the pressure is above 50 psi and the compressor continues to run you must remove refrigerent so that it is in the correct pressure range...

if the pressure on the high side is too high the compressor will be shut down...more refrigerent is not better...less is better...less stress on the compressor and system...


when the pressures are correct and the compressor continues to run fan on max... and you do not get cold air it may very well be the air temp damper door stuck..this can happen when debris is injested ....into the air box..

[maxwedge]

Good info but as mentioned none of this is possible without the proper a/c equipment, not a dyer type diagosis.