High Discharge Pressure
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High Discharge Pressure
The lowest I can get on my AC vent temperature is 58 degs. My compressor will cycle off on low pressure (36 PSI) at a fast idle but the head pressure is above 400psi.
I've changed the Compressor, evaporator, accumiliator & orfice tube, and flushed the system out several times. The oil still is black in the system when I installed the new compressor. I know that there was no oil left in the system. The only thing I did not change was the condenser and the hose assembly.
When I charged the system up the orfice tube collasped and I've replaced it twice since.
Any recommenditions?
I've changed the Compressor, evaporator, accumiliator & orfice tube, and flushed the system out several times. The oil still is black in the system when I installed the new compressor. I know that there was no oil left in the system. The only thing I did not change was the condenser and the hose assembly.
When I charged the system up the orfice tube collasped and I've replaced it twice since.
Any recommenditions?
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Evacuated the system each time for 45 minute and have a blue orfice tube, recommended by the parts house for R134A. I even tried a Red orfice tube but the pressure was even higher.
The orginial orfice tube seemed to have been a white tube if my memory is correct it was for R12. I did a coversion over three years ago and the system worked fine until the compressor went out this year. The only thing I'm thinking of doing now is completely emptying the system again and flushing the oil out then replacing it with PAG oil. In that event I'll tear the compressor apart and clean the old Ester oil out.
The orginial orfice tube seemed to have been a white tube if my memory is correct it was for R12. I did a coversion over three years ago and the system worked fine until the compressor went out this year. The only thing I'm thinking of doing now is completely emptying the system again and flushing the oil out then replacing it with PAG oil. In that event I'll tear the compressor apart and clean the old Ester oil out.
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Prior to the compressor failing I had no high pressure. The pressures were 220-240 on the high side and 45-50 on the low side. Thinking I had over charged the system I dumped some freon and the vent temperature began to rise to 70-75 degs. I believe that the pressure reduces to about 350 psig driving down the road and the compressor cycles on and on with the low pressure switch (about every 15 seconds or so) It acts as if the orfice tube is plugging up again. Any other suggestions on how to clean the system out? I'm thinking that the system is over charged with oil. It calls for 9 oz and I have about 8 oz in it.
Lead Driver
Joined: Jun 2004
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From: Amarillo, TEXAS!
You might want to read this link.
It is certainly worth looking at especially since it sounds like you have the symptoms of and precursors for this condition. I didn't realize it, but it seems Ford compressors are the most susceptible. You should be able to evacuate the system and pull the orifice tube as an initial check.
It is certainly worth looking at especially since it sounds like you have the symptoms of and precursors for this condition. I didn't realize it, but it seems Ford compressors are the most susceptible. You should be able to evacuate the system and pull the orifice tube as an initial check.
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I pulled the orfice tube and cleaned it, then pulled a vaccuum for 1 hour and measured the freon. I put 40oz in the system which is 80% charge of R134A. Pressures are better but the vent temperature is still 68 deg. I'm now thinking that I have an air mixture problem with the ventilation system. When I put the system on Max air and accelerate the air flow is directed to the defrost. So I just use the normal cool. Could there be a damper problem with the fresh air damper. If so how do I check it. I 've read the article about the Max cool problem and can not find a vacuum leak. Although the check valve may be bad. I'm not sure where the check valve is located.
Any other suggestions?
Any other suggestions?
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From: Roland, Ar
When you cleaned the orifice tube what kind of crud was on it. When I converted the system on my '89 I replaced the suction/discharge hose asmb and the liquid line. I cut the old liquid line and found a strip of old rubber about 1/8 inch wide and 2in long stuck in the hose and the orifice tube had chunks of rubber stuck to it.. If your oil is turning black I would reflush and replace the hose's. I used Pag 46 and the red orifice tube and have had no problems, my vent temp while driving is 34deg. Low side runs at 28psi and high side at 250psi at 2000rpm.
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