so my a/c works and it is cold but it doesn't seem to be very strong or extremely cold. The a/c in my 93 c4 seems to be much stronger and much cooler and provide adequate cooling at a much superior level than that of my c5. My bmw 740il does too. My ? Is, is there a common A/c issue unique to the c5?

 

Mine is cold especially if I have fan on high and selected recirculate. Suggest having a a/c tech check your system.

 

Check the A/C condenser to see if it's plugged up with grass, small stones and other junk that reduce airflow.

 

AC in a C5 AC temperature at the vent should be ~40-45 and do you have a set of gauges to measure pressures. I agree with Fast one condenser could be the issue after that pressures are the key to low refrigerant or week compressor. IF those check out blend door actuator could be the issue.

 

okay thanks so much. i am going to check everything this wknd starting with condenser. Any tips on how to go about doing so? I am sure I can figure it out if not but any and all help and info beforehand is extremely valuable and appreciated. Thank you

 

You can look up from the bottom inside the shroud and see the front of the A/C condenser if the car is on jack stands or remove the top plastic radiator hold down and push the rubber shroud forward enough to see. Mine should have been cleaned years ago, I used a long air wand for this but the archives show one made from copper tubing, one end is closed and a hole is drilled near it through one wall of the tubing. It has to be narrow enough to fit between the radiator and the A/C condenser so the junk blows out the way it came in. If the rubber shroud is unbolted and lifted up and out, the condenser can be lifted up enough to unhook it from the radiator and moved forward enough to fit cardboard, rubber sheet or Formica in front of the radiator so you don't bend any of it's fins with the wand. I used compressed air first but that didn't do much so the wand was hooked up to the garden hose and that worked a lot better. The next day a lint roller was run over the front of the condenser and that removed a lot more junk including small stones. The cleaning increased airflow from about 30% to about 85%.

 

Back to your original question, the a/c performance of a correctly working C5 system should be satisfactory In any summer condition across the US. If your other cars feel significantly better then the question is then there probably is something wrong with your C5.

Was there a time when your a/c felt comfortable? Has it gradually gotten worse?
Are you getting all the air flow out of the a/c vents; none to the floor or windshield?
Do you hear the blower speed increase from low to high with each press of the fan control?
Does the passenger side vent air flow and temperature feel about the same as the drivers side vent?
When you come to a stop from road speed, does the air temperature rise pretty quickly?
Are both of your cooling fans running in hot weather at idle?
Can you hear the compressor grinding or growling as you Switch it on and off?
Does it perform well for half an hour and then start losing air flow?
High and low side pressures plus the center vent air temperature at idle and at 2000 rpm will be very helpful to know.

Lots of possible diagnostic paths.