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Weak cooling

mrbear3800 on Thu August 21, 2008 9:03 PM User is offline

Year: 2003
Make: Buick
Model: Lesabre
Engine Size: 3.8L
Refrigerant Type: R134a
Ambient Temp: 80
Pressure Low: various
Pressure High: various
Country of Origin: United States

Hello again. My mother's 03 Lesabre is cooling poorly. Before telling her to take it to a shop, I wanted to touch base here first.

MAX, idle, doors open: 40/175psi, 52F

MAX, 1500rpm, doors open: 35/200psi, 48-50F

NORM, idle, " ", 45-50/190-200psi, 60F

NORM, 1500rpm, " ", 45/225-250psi, 52F

Compressor never cycles (not even sure if it's supposed to)

The two passenger side vents are 5-10 degrees colder than the two driver side vents. It does NOT have dual zone climate control.

A/C line from the low side port onwards is cold and wet.

I cleaned out the space between the condensor and radiator but didn't help.

The car has 60K miles.


Chick on Thu August 21, 2008 10:30 PM User is offlineView users profile

Most likely low charge, feel the accumulator, should be cold back to the compressor. The V5 compressor doesn't cycle, you need to find and fix the leak. Have the system recharged with just R134a, no sealers (was it ever serviced before) If you can find a shop that can recover and weigh the charge thats in it, would help, but in any even recharge the system amount back into a good vacuum with some UV dye if the leak isn't apparent..Hope this helps..

Email: Chick


Freedoms just another word for nothing left to lose

mrbear3800 on Thu August 21, 2008 10:49 PM User is offline

OK, thanks. The accumulator is cold. Still don't understand the temp difference between left vents and right vents. I'll probably just have them take it to the local shop we both use as they have all the equipment and are honest.

Matt L on Thu August 21, 2008 10:58 PM User is offline

My W210 M-B does have dual-zone climate control, but the difference in temperatures is from reheating the air. There is only one evaporator circuit.

When the refrigerant level is low, the left-side vents definitely suffer first. The right side can be nearly ice-cold, while the left side is completely ambient temperature. I'm not exactly sure why this is, but I suspect that it is a combination of all of the refrigerant boiling in the right half, and oil pooling in the left.

Even without a dual-zone system, the air from both sides may not fully mix before going to the vents.

GM Tech on Fri August 22, 2008 8:19 AM User is offline

I agree- the vent temp differential is a direct result of low charge-- the refrigerant enters the passenger side of evaporator air flow path first- hence when it gets low on refrigerant- that is the only area to cool.....That V-5 compressor has the new double lip seal- shaft seal already- so I'd look real good at the compressor case body for o-ring leaks-- Your system already has dye in it from the factory- so a black light and UV glasses would be a great asset...

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......

mrbear3800 on Sat August 23, 2008 8:06 PM User is offline

OK. I'll check that out, thanks.

If tha case o-rings are leaking, do they need a whole new compressor?

Edited: Sat August 23, 2008 at 8:07 PM by mrbear3800

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