Year: 1975
Make: GMC
Model: K25
Engine Size: 350
Refrigerant Type: R134
Ambient Temp: 85
Country of Origin: United States
My truck originally used a GM A6 compressor, standard condenser, and R12. I converted the truck about 3 years ago using a Seltec 16 compressor and the # 12-0568A parallel flow condenser, along with new barrier hoses and a Ford blue orifice, high pressure switch, and 3 lbs of R134 (r12 charge had been 3 lbs, 12 oz).
- About two years after the conversion I had to recharge the system because it was leaking somewhere and had lost pressure. I tightened a couple of suspect fittings, had it recharged, and went on from there. However, the next time it only took about 6-8 weeks until I lost cooling again.
- I then replaced one bad O-ring (system was down to only 5 lbs) and added about 20 oz of R134 (i don't recall the pressures) and it started cooling again. I assumed this meant I was low on R134 again, and just needed to find the leak.
- I couldn't get back to it again for about 3 weeks, and by then it was back to no cooling. As soon as I put the small can of UV dye on the port it immediately kicked in the compressor. I added about another 8 oz of 134 I had left over, just so the compressor would keep running and circulate the dye. That was earlier this week. At that point there was no noise from the compressor and I had limited cooling. I let the A/C run for about 5-10 minutes before I shut it down.
- When I went back today to use a light and look for leaks, the belt started smoking because it could not turn the compressor.
The static pressure is running about 120 on both high and low, and I can't turn it on to check running pressures. The UV dye was from the parts store and it came in a small can that was supposed to give a 1-2 oz shot. The Seltec compressor uses PAG oil (150?), and this dye was supposed to be compatible with any type of oil.
I tried turning the clutch manually with a large screwdriver braced between the three nubs on the front, but it did not move. I was not sure that it should move freely when there was no power, so I did not want to force it.
What could be making the compressor and/or the clutch lock up? Have I screwed up the compressor somehow?
Thanks,
Bruce
So about 80 ounces of refrigerant has leaked from this system over 3 years. Along with that refrigerant went some (perhaps most) of your lubricating oil.
With a system already low on oil form repeated leaks, adding a few ounces of refrigerant to spin the compressor left it without enough refrigerant to return what might have been left of the oil in the system.
I suspect when you pull the OT, it will be dry as a bone in the desert sun. If the clutch hub will not turn with your fingers, it is dead. A smoking belt? um yeah it is locked up solid.
How much oil was initially charged into this hybrid system?
B.
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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.
The compressor came originally from Arizona Mobile Air with the correct oil (I think it was PAG 150), and I followed their directions. I don't recall how much total was put in the system.
So you are saying the compressor is locked up completely and needs to be replaced, or is there something else I could do to break it loose?
Bruce
If you can't turn the hub of the compressor good chance the compressor is no longer good. I've never seen a Seltec lock up and then become free again. I tend to agree with bohica2xo lots of refrigerant losses along with oil will lead to a compressor failure. Seltec make a very good compressor but they won;t last without oil to lubricate the internals.
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