Removing AC - now system frozen?
06-28-2004, 06:12 AM
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Removing AC - now system frozen? About a year ago, I installed headers, 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
*****************
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...
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
*****************
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...
06-28-2004, 08:45 AM
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You probably didnt need a whole can of compressor oil, but it shouldn't be so much that the compressor shuts down. Is your evaporator icing up? Your vacuum pump is shutting down because its overheating I would imagine. An hour of evac time is plenty. Wonder if there is something wrong with the CCOT valve in the condenser? It controls the flow of freon based on temp. Your accumulator should be fine. Shoot, I had warranty work done on my A/C system due to a leak and the dealer said they wouldn't replace it...its been fine for a year now. The high side pressures are aweful low. I'll see what I can dig up in the service manual.
