Volvo Repair: A/C Repair, sized job, light on the water

Question
Hey Mark,

I have a 95 850 non turbo and my a/c has been blowing warm air and I checked the lines and the high side line is freezing going to the evaporator. I had the system evacuated and only 5 oz. was pulled. The shop says with a low charge the high side line will freeze, is this true? They did not find any obvious signs of leakage and suspect the evaporator core to be leaking, how hard is it to replace that part?

Thanks for your time.

Answer
  Jon, no a low charge will NOT cause the high side to freeze. An overcharge or restriction sure will though. Pretty fair sized job changing the evap. but do able. Have the system injected with dye, then shine the light on the water coming from the evap. box drain tube. if you see the dye, your problem is in that box!

Mark