78Suburban said:
Sounds like you either lost an O-ring, or either the pressure relief valve or a pressure switch blew out. R4's usually have the pressure switches retained with an internal snap ring. It is rare, but I have heard of them blowing out if the snap ring is improperly installed. The high-pressure relief valves are threaded in, and are designed to vent if the high-side pressure gets dangerously high (and for some reason the HP switch hasn't opened and caused the clutch to disengage first). Having the valve malfunction and vent below their designed pop-off pressure is less rare than blowing out a switch, but it is still rare. Having an o-ring on the hose manifold fail is not uncommon, but they usually just leak slowly rather than blowing out. The usual cause for a leaky manifold o-ring is failure to replace it after removing the manifold - reusing them is a bad idea. One other possibility, assuming you have an R4 compressor, is that you lost a body seal. Like the o-rings, they usually just leak rather than blowing out. Another possiblility is one of the hoses or aluminum hard lines on the manifold failed. Been there, seen that. Fortunately, rebulding the hose assembly and/or welding the manifold is fairly inexpensive. I can't say the same about the Freon you lost...4xcrazy said:
