My a/c was blowing hot and the compressor would not engage. I traced the problem to the Thermoswitch?? located behind the glove box on the evaporator assembly. When I jumped the switch, the compressor engaged. It did not make any noise until I charged my "empty" R12 system with R134a. The system would blow ICE but the belt started squealling like a stuck pig! I don't know if the compressor is hanging up or what.

Should I have my mechanic pull the 134 out and charge with 12 to see if the 134 and its oil caused the probelm???

Need help!! I don't want to buy a compressor if I don't have to.

 

Aren't you supposed to use special R134a oil?

I think the thermoswitch is what causes the compressor to regulate itself. I had it replaced, but it was like 4 years ago.

 

You're not supposed to just *switch* refrigerants. Something about thermodynamics. But denser gas could screw up your compressor, maybe that's why it's squealing.
~Tom

 

you can change refrigerants?