'99 Intrigue A/C Questions

[Make 'em Last]

Background -
Overhauled A/C system on '99 Intrigue 3.8L 153K last weekend: replaced V5 compressor (new), accumulator & orifice tube; flushed, purged w/ compressed air & "popped" the evaporator & condenser; replaced o-rings wherever I broke connections (used mineral oil on them). Put 9 oz. of PAG 150 oil (1/2 in compressor & 1/2 in evaporator), pulled a vacuum on system for over an hour, and put 3 cans (12 oz) of R134a in system (used hot water to help empty cans). Service bulletin called for 2.25 lbs. (3 cans) instead of 1.88 lbs. (2.5 cans) of R134a. With thermometer in center vent, have seen as low as 38 deg. F air with A/C on recirculate (85 deg. F). Both electric fans (on radiator) work on low & high speed. System has run for an hour at a time with no problems - on Interstate with ambient temp at 85.

Problems/Questions -
A/C seems "finicky" at higher ambient temperatures - around 95 deg. F. It's like solving a puzzle adjusting the inside blower speed to the driving (idling, stop & go, low speed highway, etc.). A/C turns off, and comes back on when you turn off & back on, change blower speed, etc. Have proper gauges and GM service manual, but don't understand what I'm supposed to see exactly as far as the pressures versus ambient temp. Can you fellows figure out what I'm missing? Do I recover some refrigerant or add some? Would feel more comfortable doing this if I knew what I was trying to achieve (pressures). Also, once I start recovering or adding, I'll easily loose track of how much is in the system. Did I post this in the right place?

[BNaylor]

If what you are saying is true then the revised spec pf R134a refrigerant charge of 2.25 lbs or 36 oz is correct so I would not recover or add any.

The pressure increases based on ambient temperature even with a proper charge. What are you getting on low side and high side pressure at 95 degrees?

[Make 'em Last]

Originally Posted by BNaylor

...What are you getting on low side and high side pressure at 95 degrees?

Checked it today in the driveway - 94 degrees in front of condenser. On M2 blower setting (Lo, M1, M2, M3, Hi), got 46 / 225 psi & 58 degrees out of center vent. This with doors open and on recirculate. Switched blower setting and compressor cut out (LED went out & could hear clutch disengage). Played with the blower speed and got a/c to run on Hi blower setting - 50 / 240 psi with 62 degrees out of vent. Both radiator fans were running on high speed. Idle speed was about 740 rpm.

[brcidd]

You have the dreaded intermittent A/C control head problem- found on a lot of Malibus and Intrigues

Easily fixable- clean contacts on back of master on/off switch on blower motor control and all will be well...

[krivasauto]

Originally Posted by brcidd

Easily fixable- clean contacts on back of master on/off switch on blower motor control and all will be well...

Can you elaborate? Is this for both styles A/C control (manual and automatic)?

[brcidd]

It is for manual systems
it has been written up many times on the a/c forums-but I don't believe this forum allows links to them..

I have repaired 20 or 30 in the last ten years

you remove the blower motor selector switch- clean away all the hardened grease off the a/c compressor control brushes, then use a light oil and reinstall- the grease actually turns to a hardened "earwax" type substance which disconnects the compressor control..