My air conditioning went out this last week. Ice cold when I got out of the car. Nothing when I get back in.

I rented a manifold gauge and a vacuum pump.

Connect manifold gauges to the lines and the pressure in the system was equal to atmospheric. But here is the interesting part. After completely evacuating the system (which was empty) with the vacuum pump the gauge read 29 in Hg of vacuum. And remained there with the pump disconnected and the valves closed for ten minutes.

After charging the system with 12oz 134a dye mix the system began functioning again and after about 6 hours I have been unable to locate any kind of leak in the engine bay with a black light. Now I'm no expert here but this seems to defy the laws of physics. It would seem to me that any leak significant enough to allow my air conditioning to reach atmospheric pressure between the time when the cutoff switch disabled the system (four days before initial pressure tests) and the time when I hooked up the gauges to the system would not allow a vacuum to form within the air conditioning system.

 

What year car is this?

 

the work of dragons.

 

94, so it's 134a.

 

Hmmm, never mind, pulled the evaporator and it had blown a coil.