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I recently posted another thread about this. The background is that for many years I have had an ac leak which in some cases over a period of time but on occasion suddenly loses a certain amount of charge. The odd thing is that once that happens the system retains the rest of the charge.
In any event I decided to fix this. I injected a UV dye and it looked like I could see some dye near a couple of fittings. In any event since I was taking the system apart I replaced all the seals, the schrader valves and the compressor shaft seal. Pulled a vacuum close to 30" Hg with a vacuum pump before recharging. After running it for about half an hour I turned off the pump and closed the valve and the system held the vacuum for almost an hour. On that basis I concluded that the system was leak free and recharged and everything was working well for several days with nice cold air.
It has been cold recently so I dod not need ac until today. I turn the ac on and no cold air. Initially even the condenser fan was not running. After pulling out the relays it started working so I assumed it was a coincidental electrical problem. But still no cold air. I checked the compressor clutch coil resistance and the signal to it and it was fine.
I then hooked up the manifold gauge set and it read 100psi high and 10psi low so guess what. It has lost charge again just like in the past and very suddenly. It possibly is on the threshold where the pressure switch may shut the system down due to low pressure.
I'm now suspecting a faulty pressure release valve on the compressor. I will be jacking the car up later today to inspect to see if I can spot any oil around it which would confirm my theory.
Other than this does anyone have any ideas what could cause an apparently sealed system to suddenly leak like this and how to I go about trying to track it down.
In any event I decided to fix this. I injected a UV dye and it looked like I could see some dye near a couple of fittings. In any event since I was taking the system apart I replaced all the seals, the schrader valves and the compressor shaft seal. Pulled a vacuum close to 30" Hg with a vacuum pump before recharging. After running it for about half an hour I turned off the pump and closed the valve and the system held the vacuum for almost an hour. On that basis I concluded that the system was leak free and recharged and everything was working well for several days with nice cold air.
It has been cold recently so I dod not need ac until today. I turn the ac on and no cold air. Initially even the condenser fan was not running. After pulling out the relays it started working so I assumed it was a coincidental electrical problem. But still no cold air. I checked the compressor clutch coil resistance and the signal to it and it was fine.
I then hooked up the manifold gauge set and it read 100psi high and 10psi low so guess what. It has lost charge again just like in the past and very suddenly. It possibly is on the threshold where the pressure switch may shut the system down due to low pressure.
I'm now suspecting a faulty pressure release valve on the compressor. I will be jacking the car up later today to inspect to see if I can spot any oil around it which would confirm my theory.
Other than this does anyone have any ideas what could cause an apparently sealed system to suddenly leak like this and how to I go about trying to track it down.
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