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Saturn blows hot, pressures ok?

kpedigo on Thu May 12, 2011 2:34 PM User is offlineView users profile

Year: 1997
Make: Saturn
Model: SL2
Engine Size: 1.9L
Refrigerant Type: 134a
Ambient Temp: 88
Pressure Low: 25
Pressure High: 155
Country of Origin: United States

I know its a noobie question but... My ac is blowing hotter than ambient air, and I am positive the "doors" are in proper position. (its not heated air as if I swithch to heat it gets much hotter). The compressor runs no cycling, no unusual noise, the pressure readings in the post are at 2000 rpm. I feel no cold lines anywhere I can reach, but no excessivly hot spots either. I am thinking no r134 circulation, probably tev? Any thoughts would be appreciated.

mmm hmm...

mk378 on Thu May 12, 2011 2:45 PM User is offline

It appears you have a variable compressor system. Those must be known to be properly charged (by weight) before trying to diagnose. Possibly it's just a leak-out. The low side is regulated to 25 psi over a wide range of conditions both normal and abnormal.

kpedigo on Thu May 12, 2011 3:29 PM User is offlineView users profile

Thanks for the reply mk .
I am sorry for the vague post, I don't multitask well.
I was trying to get some insight into what I should suspect needs repair or replacement. I am going to open the system to do some other things to the car soon, I will have the tire store down the road reclaim the 134 before I open it. My situation is basically this, I do not know what may have been added to the system in the past, but after I fix the rest of the car, I plane to evac and recharge the system here. So, what I would like to know is your experienced best guess at where to look for most likely culprits. Compressor runs ok, system has never been open or de-pressurized that anyone is aware of, small cans may have been added in the past. I get no condensation or temp change of any kind at reciever or expansion valve. If you were to bet, would you suspect the exp valve, or drier, or both?
I hope I am not coming across as a smart a$$, I know just enough to be dangerous...

mmm hmm...

mk378 on Thu May 12, 2011 4:01 PM User is offline

My best guess right now would be that it's simply undercharged. Have the shop remove the refrigerant in a way that they will weigh how much comes out.

kpedigo on Thu May 12, 2011 5:36 PM User is offlineView users profile

Thanks again dude,
as for weighing the removed refrigerant, I'll ask, but I doubt these guys can add or subtract all that well.
Do you really think that an undercharge like that will cause no cooling whatsoever? I don't doubt what you say, but it seems to me there would be some (if weak) cooling or evidence of circulation, but like I said, I don't know that much.
It would be excellent if all I have to do after re-building this engine is re-charge and go...

mmm hmm...

GM Tech on Thu May 12, 2011 9:58 PM User is offline

Do a forum search for saturn and see what a PITA they can be to get them to start pumping. Gotta love those rotary vane compressors!

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

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