Automotive Air Conditioning Information Forum

i posted another post asking about oring and gaskets however i have another question. I have a 1999 chevy silverado 5.3l 4x4 with all new ac parts i installed everything correctly, vacuumed my lines for about an hour, added the correct amount of 134a using gauges. however when i turn my ac on it works fine for a few hours of driving when all of a sudden my oring starts leaking at the condenser. i tried several times over the same steps in correctly installing the system but it keeps blowing the orings either from the top of condenser or bottom it varies. its like the system is just building too much pressure and finding the weakest point to blow out the 134a. i know i am not adding too much 134a because ive even tried it using less than needed as in 24oz. i am adding the correct amount of oil and type. i vacuum the lines every time im not sure what is causing it i replaced the high pressure switch and also the low switch. any help would be appreciated. thanks

I recently encountered similar on my 1998 Nissan Frontier after my high pressure line developed a pinhole and I bought a replacement line, have a thread on this on this site started about late June. For me, it turned out that the aftermarket part was made incorrectly, and the metal end fittings would not seat fully. But what actually made the O-ring leak (first time after it worked fine for 400 miles over a week) was that my fan clutch was defective so my refrigerant pressures were too high, and that expelled refrigerant and some oil out past the O-ring, while at idle.

So check your fan clutch. I will add that my engine did NOT run hot with the bad fan clutch, even in Arizona summer heat wave. I could tell my fan clutch was bad visually by slow fan speed and by the rolled-up newspaper test.

If your truck has electric fans instead, make sure that these are all running.

And you need all the factory fan shrouds to be in place, important for condenser and radiator cooling.