The original dash ac used R12. When I had to recharge it went with R134 but could never keep it loaded and last year swithed to Propane. Anyway never had great cooling.

The engine condenser is pretty small and thinking about installing a large unit on the back of the engine radiator. Has anyone tried this?

There are just a lot of rules on the use of R-290 (propane) as a refrigerant still can not be used as a home A/C refrigerant and the charge is limited to 0.33 pounds in most other cases. Not sure about using it in a vehicle. My old knowledge is that as a replacement for hydrocarbon refrigerants it was not very good or even recommend and in an R22 compressor it had fire problems.

The addition of a fresh air condenser using R134 or one of the newer refrigerants should help, the charge will need to be carefully adjusted. changing the evaporating device (R12) is recommended but I think that's not really necessary.

The dash A/C in RV's at least in my experience is they are not very good period.

I have had 4 RV's it almost was acceptable when converted to R134 in my 86 Winnebago, never was successful in my 3 Barths so far!!

There are some new system sealers on the market, I used one in my home split system R404 and it has been good for the last 2 years!

Good Luck!

I have the same problem with trying not to melt while I drive. I don't have dash ac so I run both roof ac when we travel but I can't keep my generator running more that 30 min because it shuts off ( after many new parts ) I think I am going to make a divider right where the kitchen starts and just run the one ac and try that well when I fix the generator.