Hey guys, just found your forum after searching to find some specs about the a/c system in my saturn ion. The a/c has been blowing hot sometimes but for the most part it blows pretty damn cold, its usually when the car is at a stop light. I just today recovered the a/c system and pulled out 1lb of refrigerant (car holds .9lb) and vacuumed the system as well. the had absolutely no leaks after leaving sit for 15 minutes gauges did not move. After i had recharged the system system the gauges were looking good at 30 on the low side and 225 on the high side at idle. when i had set engine rpm to 2000 the high side went up to 250 and as soon as i had let off the throttle the compressor kicked off. So basically what I am trying to find out is when the high pressure switch kick on/off at what psi and when does the low pressure switch kick on/off at what psi? And also I only found 1 pressure switch near the a/c comprerssor, where is the other switch located?

 

In most A/C systems, the pressure safety switch is actually two switches in the same housing. The low switch will stop the system from running if the pressure is below limits, and the high pressure switch stops the system if the pressures get too high.

Tell me, are the discharge side refrigerant lines really hot?

I am no expert on A/C, but I would interpret the gage readings as one or more possible problems as follows:

Restricted or blocked condenser fins (power washed them lately?)
Refrigerant overcharge
Faulty condenser cooling fan
Air in the system (unlikely, you just vacuumed it)
Expansion valve stuck open allowing excessive amounts of refrigerent through evaporator

 

i could not tell you if the discharge lines were hot. condenser fins are fine, care has never been pressure washed and i had checked the fins yesterday. i know refrigerant is at a perfect level i put 1 lb in the system, the factory said .9 lb, .1 extra would be fine. air in the system is ruled out as it has just been vacuumed and also the system i know for a fact has no leaks. the one thing we were thinking is a possible expansion valve as you stated, but we were also thinking it could the a pressure switch. I ask becuase I work on big rig trucks and there a/c system has 2 pressure switches one for low and one for high. Also would you be able to tell me what the cutout pressure is of the switch, and if im correct then both switches are near the a/c compressor correct?

 

Make sure the cooling fan comes on with the A/C.

 

yes the cooling fan was on and running at all times when i had the a/c on. and my car has never had any overheating problems.

 

Is the airdam in place?

 

what air dam?

 

Mike -- let's go back to the start .....

Here's your original comment ---> "The a/c has been blowing hot sometimes but for the most part it blows pretty damn cold, its usually when the car is at a stop light."

In my simplespeak mind, I read that to say you got good A/C while driving, but not when you stopped at a traffic light .......

An air dam is a plastic shroud (or cover) that directs the airflow through the radiator. If that is not in place, the fan cannot work at peak efficiency to cool the refrigerant going through the condenser. Oh, and condensers may LOOK clean, but road bugs/trash etc can get stuck inside the coil, decreasing the efficiency. A good power wash with the wand when you wash the car helps a lot.

 

AirDam: It's black hangs down under the front bumper about 10 inches back. As said it dams ans directs air to the radiator mostly while at idle.

 

I'm Sorta With OceanArcher at this point. Not knowing a whole lot about them and also not having a full set of gauges. I usually use the el-cheapo single gauge supplied with a can of R134.
The pressure switches on a car anyway tend to be two switches in a common housing and are indeed safety switches, a high pressure and low pressure. And located on the compressor.
Sitting at a stop light with no air flow moving the A/C will tend to run warmer, not hot. 'Specially if it is a R134 conversion, although my conversions run a whole bunch colder at 110 degrees than freon did.
The compressor kicking off can be and indication of normal cycling! That is how they run. However it is because the loss of the clutch signal as determined by circuitry some where else in the system so why did the compressor kick off? A meter should tell you, it cycled off so the signal is now gone or the signal is still there and a safety switch caused the compressor to quit running.
I guess lacking any additional information, this is where I would buy a book of words on servicing the thing.