Air Conditioning - again

[GoddardCat]

The saga continues. I put in a new microfilter and a can of coolant last week. The gauge on the hose was already in the "good" area at about 30 pSI and the aditional coolant raised it to about 35 PSI and the AC was colder. On a four hour trip the AC worked well at first but became warmer though still cool. After sitting overnight it was very cold again and did the same warm-up thing on the way home and also blew fog out of the vents. The car is a '94 325ic with the non-digital climate control. The two temperature knobs have no effect at all when turned and I'm wondering if there might be an electronic problem that is causing the AC to not work properly. I know there is a fix for the digital climate control on later models that involves replacing a capacitor. Does this hold true for the analog controls like mine? The only other thing I can think of is that the AC is freezing up maybe because of too much r-134 though the gauge shows it right where it should be.
Any help?

[LuvThatSam]

Your A/C compressor may have a leak.......Do you have on of those tools that has a sensor at the tip which you put it near A/C parts to detect a leak????? If you dont, you need to get one and go around the car with to try and determine where the leak is.....You may have a bad A/C hose or a bad compressor.......

[IBreakStuff]

You're saying that whenever you let the car sit for a while and "cool down", like overnight and then the A/C is fine again? At least for a while then it gets warmer and warmer?

If that's the case, it sounds like your condensor isn't cooling properly and you're losing efficiency. Either it's blocked with mud, or your aux fan isn't turning on. Or possibly your belt is worn out and as it heats up it stretches and slips, causing the compressor to not turn as much as it's supposed to.

Judging by it working just fine after a night of rest, you're obviously full of R-134a.

If all of the things I mentioned above are fine (condensor not blocked, aux fan turning, and a/c belt not slipping) then you are correct in that it's a control problem. There's an actuator that moves a "flapper" door and it might be slipping and letting warm air in.

Let us know what happens.

Bryan