Hi All,

I upgraded my truck to R134 a while back (cleaned system, new expansion valve, o-rings, proper oil and R134 charge) and it works great, BUT after 15 or 20 mins the system over-pressures. If I water down the condensor the pressure snaps back to normal. I've noticed that the fan clutch is engaging only intermittently and am wondering if it's nearing end-of-life.

Can anyone tell me how long they typically last? Not long after I got my truck, it needed one, though it had 195k miles on it at the time (not sure how many times before it was replaced). I've now got around 70k miles on this one and I would suspect that is too soon for it to crap out. I did use an OEM isuzu one and not an off-brand.

Anyone have any ideas? I'm hoping that it's just the clutch and not a function of the R134 conversion (higher operating pressure?). The pressure does run a little higher than it did with R12, I am running the proper oil charge and about 80% the R134 as the spec'd R12 weight. Cools fine until it over pressures or when I'm spraying a little water on it.