a/c problem

[777884chevy]

the a/c on my 84 gmc is blowing so cold that it is freezing itself?? I don't know how else to describe it. You know when you open up the freezer door on the old refrigerators and they need defrosted cause of all the frost? well that is happening in my vents and air can't pass through .
It spits out little chunks of ice and has that vapor effect like opening up a freezer door. Man this is weird. lol Anyone have this happen?

It's not the stock a/c system. This is originally a non a/c truck. Someone put the a/c guts from a mitsubishi truck into this one compresser and all and boy it works overkill.

[VileZambonie]

That's called evaporator icing. Moisture surrounding the evaporator is freezing. 1st Check the evaporator drain case to make sure it is clear. 2nd, check your system pressures. You say this is out of a Mitsubishi. I believe the Mitsu's used a TXV (Thermo expansion valve) system, where as your truck came with a CCOT (Cycling clutch orifice tube) system. If someone just rigged it up so the compressor just constantly runs and the TXV valve is not working correctly evaporator icing can also occur.