I replaced the compressor about 2 months ago, which came with brand new O rings. 2 weeks later, one of the O rings gave out. All my freon escaped. Replaced the O ring, and a week later the other one gave out. Replaced that. Just few days ago, one of these two gave out again. Making it the third O ring replaced in a two month period.

I don't think I'm over filling it, I go off of the gauge on the hose when I fill it up with freon. Plus I was told it takes 2 pounds, or 32 ounces. I've always filled it up with two 12oz cans. That's a few ounces short. I'll add that I'm not vacuuming out the air, I'm doing all this myself and I don't own that machine.

Any thoughts as to why I keep blowing O rings? Today when I bought the new O ring I asked for thoughts to the auto parts guy, he had no clue. He only told me that by looks of my blown O ring, it looked like it was pinched. Leading me to think that I'm over tightening the hoses. So I've tightened just the necessary amount this time, we'll see it it lasts.

 

estunum, first, evacuating a freon system is very vital to the system functioning properly. I am a universal freon tech. Will the system blow cool air, kinda, but it will be much colder after the system has been evacuated.

As for the O-Ring, it is possible that by not evacuating the system, you are forcing the system to run at higher pressures too, leading to o-ring blow out. Otherwise, I would think that you are either 1) not getting the o-ring installed correctly (ie pinched) or 2) the joint is not tightened enough and you are leaving a gap for the o-ring to be pushed out. Keep in mind that the freon systems of vehicles can run upwards of 600 psi. That is a lot of pressure on a small rubber piece. The two metal surfaces should come in contact and seat one against the other. If you simply move the hose to the port on the compressor with the o-ring installed, you should be left with a slight gap (1/32"/1mm) before you tighten it down. This will ensure you are positively "crushing" the o-ring, but you are not overly crushing it either.

Another thing that I would recommend you try to do is get a little bit of the appropriate freon oil (because your car is an 89, should be R-12 oil). Put some of the oil on the o-ring prior to putting it into the recess. The oil is going to help the o-ring stick to the metal surface and prevent it from moving as you are trying to get everything together. This should eliminate any pinching issues you may be having.

Hope this all helps.

 

Many thanks Thermo, prompt and detailed reply. I will try what you're suggesting. My car doesn't take R-12 anymore. My local jaguar mechanic converted to R-134a a while back. It is the only reason why I'm filling it up myself.

I will get the system vacuumed. I will double check each ring is seated properly and it's tightened enough to achieve the proper seal. I'll add the appropriate oil as well.

Again, thanks for the help