850 T5 airconditioning

I have a similar problem on my 94. What I have found out is that dust and debris gets down into the evaporator core which in turn rots it out. When this happens the system is not able to hold the pressure it needs to keep running and shuts down the compressor. You probly need to find a reliable shop near by and have htem check it out. It may be as simple as a pressure sensor or it could be the evap core.

There are a couple of things that are likely. There's a temperature switch on the back of the compressor that cuts the A/C off if the compressor gets too hot. This seems to be set too conservatively, and is not present on later cars. Just bypassing this switch may get rid of the problem. The clutch on the compressor seems to have trouble re-engaging when it is hot, and rewiring with a relay seems to help in this case, as it eliminates the voltage drop in the A/C circuit.