Automotive Air Conditioning Information Forum

I hope someone can help me.

1988 Buick clutch/orifice tube system. Converted to R134A 15 years ago.

Cooling was great yesterday at startup when driving for 5 miles and the suddenly very poor/no cooling.
Under normal working AC system interior center vent would give 38 - 42 degrees F output air

Checked today.....
Ambient 88 degrees F, 42% humidity

Static pressure: Low side - 98 PSI, High side 98 psi.

Idling at 600 rpm, AC clutch engaged.

After 10 minutes of operation, windows open, blower on high, AC temp set to 60 degrees F, radiator cooling fans on

Accumulator temperature - 68 degrees F
Evaporator temperature - 69 degrees F
Interior center vent temperature - 68 degrees F

Low side pressure - 60 psi
High side pressure - 160 psi


Test data with engine at 2000 rpm...….

Accumulator temperature - 59 degrees F
Evaporator temperature - 64 degrees F
Interior center vent temperature - 60 degrees F

Low side pressure - 40 psi
High Side pressure - 275 psi

Any suggestions on what may be wrong?

It's a 1988 Buick Park Avenue Electra with 3.6L engine. According to the service manual and what I can see visually, the system uses an Orifice Tube.

HR6, DA6 Compressor w/ Clutch

From all my data does this look like a bad compressor, and nothing else?

The clutch bearing is making noise so I'm going to just replace the entire compressor. I just don't want to find out that some other component or blockage is my main non cooling issue.

To repeat the system was cooling just fine for the first 5 miles yesterday and then just suddenly stopped cooling.

I'm leaning towards a bod compressor, I'm not any expert in AC, so just looking for guidance and thought all the data that I supplied could possibly alert someone that had the similar problems. Isn't my low side pressure kind of high at idle?

Just as a follow up....

I replaced the compressor, accumulator, orifice tube, flushed the system, added 8 oz of PAG150 oil, pulled vacuum with no leaks, added 30 oz of 134A Freon.

Everything is fine, 40 degrees F out of the vents on an 86 degree, 52% humidity day.

Al9 wrote:Good, so you replaced a dying comp in time before it had a chance to seize up and do more damage. Enjoy your cold air.

Yes, I found no metal on the orifice valve, but it was clogged with other muck.