Automotive Air Conditioning Information Forum (Archives)

Metal Man on Fri July 06, 2012 9:00 PM

Year: 1999
Make: Buick
Model: Regal
Engine Size: 3800
Refrigerant Type: 134a
Ambient Temp: 97F
Pressure Low: 60
Pressure High: 350

OK guys i got one that has me stumped ...sorta.

Guy brings in a Duel Climate 1999 Buick Regal today with no AC. Compressor will not engage. He has replaced the compressor and Accumulator his self trying too fix the problem.

Digital control head says the out side temp is 13 F ( It was really 97 F). So i replaced the control with a used control head from the salvage yard. This fixed the problem AC compressor now kicks on and works.Only passenger side is cold.

Next i removed refrigerant and weighed it. The system was full of air and 12oz low on 134. I vacuumed the system down and installed the correct amount of 134a( 1.88lbs)

Now i have two problems.

Problem #1. Only the passenger side ac is working. First i thought it was the low charge causing this but after the proper charge was installed the problem was still there. So next i looked under the driver side dash and located the actuator. I can see it move as i adjust the temp from hot to cold. Only thing i can figure is either the blend door has come loose from the actuator or the actuator its self is broken on the inside were i cant see it.

Problem#2 High pressures. Both the low and high side are high. Again the system has a proper charge. At idle I'm getting Low side 60 High side 350. When i run the RPM up to 2000 i get a Low side 42 High side of 400. Vent temps are about 60 on pass side. 100+ on driver side

So I'm thinking the condenser is about half blocked (not sure though). Fans are working fine and there are no obvious air blockages. I run water over the condenser and my pressures dropped to a low of 30 and high of 250.

Far as i know the orifice tube has not been changed.

Right now my plan is to remove the actuator and look it over.Am i on the right track here?

Not sure if i should tell the customer he needs a new condenser or not. I hate to have him spending money if its not gonna help.

I'd like your thoughts on this and any advise is welcome. I'm sure some of you guys have battled this duel climate cars before.

Dougflas on Fri July 06, 2012 9:39 PM

I think it's either the fan/airflow or condenser. Water has confirmed that.

mk378 on Fri July 06, 2012 11:13 PM

Ask what was wrong with the original compressor. If it had internal mechanical problems, the condenser and OT are probably clogged with bits of metal.

GM Tech on Sat July 07, 2012 8:23 AM

A '99 W car is famous for the cracked actuator gear on driver's side actuator- did 2 already this year...take actuator off and open it up- you'll see what I mean..

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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......

Metal Man on Sat July 07, 2012 1:38 PM

Thanks guys.

He actually had the old compressor with him. I looked it over and it was in good shape best i could tell.He changed it simply because he had no idea what the real problem was.

GM Tech I'm gonna pull that actuator Monday.

As for the high pressures I'm gonna suggest a new condenser and orifice to him. ( Can you believe GM actually mounted the OT in line under the Vacuum Booster on this car. Vacuum booster has to be removed to change OT. )