Automotive Air Conditioning Information Forum

I just signed onto the forum in hopes of solving what is becoming an expensive mystery. I have a 93 Dodge B150 Ram van with 5.2 magnum V8 engine. About five years ago I replaced the entire AC system, every single piece with new parts and converted to R134. Worked great until this summer. An O-ring blew on the fitting at the compressor. Shop said bad compressor and replaced it and the expansion valve and drier. Blew again a week later. Replaced the O-ring and it blew again about a mile from the shop. So, second shop says the first shop didn't install the O-ring properly, some part of the fitting was missing. Installed it and it worked for three weeks, blew out again today. So, now the shop says high head pressure is the problem. I ask why, they say they don't know. Since I'm spending about $100 every time this happens I would like to find the problem, once and for all. A friend suggested the fan clutch could be failing or bad expansion valve, but both are relatively new. I'm at a loss and out of my depth here. I'd appreciate any advice anyone could offer. Many thanks, in advance!

In order to diagnose system issues, you need a gauge set. Both high & low side pressures are important.

1)
High head pressure is not a compressor fault. It is in fact evidence of a compressor in decent shape.

2)
Repeated O ring failures at the same fitting indicate a bad fitting or improperly sized O rings.

3)
A dead fan clutch can raise pressures, and reduce cooling. Certainly a thing to check, but unlikely to be the reason O rings keep failing in the same spot.

4)
A blocked expansion valve usually results in poor to no cooling. very low pressures on the low side and high side pressures at or below normal - only a gauge set will tell you for sure.

A good quality gauge set is less than 100 bucks:
http://www.ackits.com/refrigerant-guage ... oses-24615

And you only spend that once - instead of every time a tech can't seem to find a problem...