My 85 crew has a Cummins conversion done to it, and last week the belt started squealing. I thought it needed a new tensioner, but I found the pulley on the compressor was the culprit. I bought a reman compressor, replaced it, vaccumned the system down and then added R134A to the system. I backed it out of the shop and finished filling the system. Temp check showed I was getting 32*F air out of the duct on the passenger side. That day I took it for a drive and the front people were comfortable, but the back seat was still noticably warmer. I guess I'm going to pull the dash back apart, and make sure all the duct work is sealed up and hooked up, as air flow was pretty miserable out of the vents. The other mod I'm going to do is put a relay that switches on when the fan switch is on "high". That way the fan motor sees true battery voltage to get a little more speed then the typical voltage drop a person sees through the switch.

I think the cooling part may be up to the task with the fact of the cold temps even with R134a in the system, its just a matter of getting the air moved around the cab.

Michael