About a year ago, I swaped heads and cam which required removal of the AC condensor.

Upon re-assembly, I pumped down the AC system with a commercial vacuum pump and charged the system with 2 cans of R13a and a small can of compatible compressor oil.

The AC system worked fine for a year but recently it began to freeze up after about 45 minuntes of highway driving.

So I replaced the accumulator/drier and pumped down the system again. Unfortunately, there was a system leak that was not detected until after the pump was on for several minutes. In fact, the vacuum pump shut off and the system returned to normal atmosphere (****!).

Becasue it was Sunday, and I could not obtain another fresh accumulator/drier. So I fixed the leak, and pumped the system down again. When I tried to fill the system, the following occured:

1. The system would only take 3/4 of a can of freon
2. The compressor pump clutch was engaged (AC on, fan max)
3. The low side (blue) pressure reading was in the red-zone - too much pressure
4. The high side (red) was about 100-lbs

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Questions:

1. I assume I can replace the accumulator/drier again and start over without diffuculty; I am presumming the system is FULL of moister and that the evaporator freon valve is freezing up causing the system to read too much pressure.

2. If not, what are the classic signs of component failure when the low side (blue) reads too high? Is this a valve problem?

3. Why does my vacuum pump shut down after about one hour; I checked the oil level before pumping? It seems to recycle and will again pump after shut down but only after it fully cools?

4. Is it possible that the system has too much compressor oil; some of the oil drained from the condensor when it was sitting on the garage floor 12 months ago - this is why I initially charged the system with a small can of compresor oil? If too much oil, I assume using compressed air to force the oil out is a NO-NO becuase it introduces more moister into the system.

Thanks...

 

The high side pressure is too low. Sounds like there is a blockage.
If your system was icing up, I'd check the pressure switch as well.

edit: If there is moisture in the system, you'll destroy the compressor.

 

OK; can you tell me where the pressure switch is located?