Redou

[redou]

Hello,



My buddy has an A/C problem.
Won't get cold.
96' GMC / Chevy Van 134A system

ENGINE OFF
Gauges say 120 high, 110 low

A / C CONTROLS SET TO MAX or NORMAL, ENGINE IDLING NORMALLY, BLOWER ON
Compressor Clutch not engaging.
Compressor jumped from Battery - now Clutch engages - compressor on
Gauges now say 125 High, 110 low
A / C radiator has air flow
Low side valve shoots out mist when gauges are being attached, I think
system has 134A in it.

ENGINE REVVED UP TO APPROX 2000 RPM
Compressor running (clutch engaged), set to Max or Normal, blower on
A /C radiator has air flow
Gauges say 150 high, 70 low
Still not cold
Compressor seems to be making a high pitched whining noise, but not
very loud, this may be normal, I am not used to this vehicle's sounds.
No bearing rattle from compressor.

Would appreciate any suggestions.

Redou

 

[zora]

the compressor not engaging until higher speeds/pressure sounds like the low pressure sensor may be failing but that you still dont get cold at those higher speeds sounds like maybe a blocked system. Does it use an orifice vale that may be blocking flow.

 

[redou]

Hello Zora,

Thanx for your reply. I perhaps did not write the post carefully. The compressor clutch engages when I jump it off the battery, so compressor is working at high AND low speeds. I think it has a valve in the system, my friend calls it an 'expansion' valve. I do not know if that is correct wording or not. It seems there is also another valve in the compressor that can affect the gauge readings.

I read elsewhere that:

Low side: HIGH - ( I am getting 70 to 110 on the low side)

High side: LOW - (I am reading 120 to 150 on the high side)

Indicates:

• Compressor valve problem. (different from the Orifice valve)

• Missing orifice tube.

Does this make sense?

I doubt anything is missing because the vehicle owner says system was getting cold previously.

I was hoping someone could interpret the gauge readings
for me.

The charts I can find on the net seem to indicate that a
blocked orifice valve will result in a High reading on the high side whereas I seem to have a Low reading on the high side.

Anyway, thanks for your timely reply.

PS - I cannot figure out how to edit my first post, don't see
any EDIT button.

 

[zora]

the edit button is on the bottom of your post right side, depending on screen resolution you may have to shift to right