Dash air is not very cold on our 1989 GV Oshkosh chassis with the 8.2 Detroit. I don't know if previous owners converted over to R134 or not. No tag, no record of it. Are there some changes I have to make in order to fill with R134? Do I have to purge system first? Different components? Effects if freon and R134 are mixed?
My experience has been that if the system has been converted, it will have R134 valves on it where you add freon. R-12 valves are a different size.
I heard both that you have to evacuate the entire system and that you don't but my bet is on yes, you need to evacuate. There is, I'm told, a freon that can be added to an R-12 system but it runs about $50 per can. I wasn't able to find any R-12 when I was looking for it. I just had a new compressor installed at Foretravel with R-134 conversion. Total cost was $600, including labor. For once I had the least expensive compressor instead of the most expensive. Our dash air cools the entire front of the coach in 90+ degree weather. No need to run the generator and the roof air. Even our furry friend Trip stays comfortable.
If it is not cold, the freon is already gone There is a kit for adding 134, including valve connections and guage. Around $35. It is for a car, so you'll need another can or so. I did my '87.
yes you MUST purge the system
the oil needs to be flushed out and changed to r134 compatible oil and the system needs to be placed under a good vacuum for at least an hour and checked for leaks. IF you don't take these steps the compressor WILL fail. It may fail anyway because of the increased operating pressure of r134. also, it will tend to leak out over time unless you ave the hoses change to barrier type hoses. as an alternative, you might find gas mixtures such as freeze 12 that claim to be compatible. Also, don't charge the system over 80% of rated capacity.
good luck
Norm, Freeze 12 that Rick mentioned is the one I was trying to think of that is compatible with R-12. As I recall, there was some concern about R-12 compatibles containing butane. eBay Guides - Freeze-12 Refrigerant R134a (http://reviews.ebay.com/Freeze-12-Refrigerant-R134a?ugid=10000000005615895) The explosive nature of butane was a concern for me.
Regarding changing the lines, I am quite sure that the 40 plus feet of lines were not changed on my my U300 and the air works great and hasn't leaked for nearly two years since I have had it.
In my FTX, most of the AC lines were metal and didn't need changing. It was only the flexible lines in the back and front that I changed to the barrier type
Thanks everone.
Rumour had it awhile back that R12 could be gotten in Minnesota. This was about 6-8 years ago. I had gotten the connecting equipment from someone and the cans of R12 but never used it. Subsequently gave it away. Don't want to go R12 route again.
Yesterday I did go over all the hoses for the AC and tightened all the hose clamps. (some seemed a little loose). The hoses all looked good.
If I'm understanding you correctly, it's not possible to put the wrong freon (R134) into an older (R12) freon system without adapters?
That, at least, would make sense. Not everything does.
Craig
That is a correct... Not possible to add r134 to r12 valves without adapters, which are usually screwed on with some thread locker once converted.
Don