AC problems with my LS swap in my 87

[Alex Stilwell]

I have a problem I hope someone can help me with. I put a LS1 5.7 from a 2000 Z28 Camaro in my 87 Silverado, everything runs as it should, I've been driving it for 4or5 months now with no problems. I'm now trying to get the AC to work. I went to a local shop and had lines made up to fit my truck, it held a negative charge when we vacuumed it down, but after that I charged it there is no pressure on the high side. I'm wondering if my compressor went bad or w hat ? The AC was working in the Camaro the last time I started it up before taking the motor and transmission out. Any help from LS swappers would be greatly appreciated, I'm puzzled as to what to do
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[eagleuh1]

Is there pressure on low side? If not, check for oil residue around charge valve, possibly didn't reseat after charging. Also check to make sure all o-rings are still good at all connections. Mine leaked out the charge valve very slowly. Replaced with new internals, sealed second time. Good luck. Jim

[bnoon]

Is the clutch engaging ok? If so, there should be high side pressure. If not, you may have a bad pressure switch or may need to jumper the clutch to get it to push the high side a few seconds before it kicks in initially on its own.

[mattcrp1]

When you say "no Pressure", do mean the pressure on the high side does not change from the low side? If so You may want to check the orifice tube or thermostatic expansion valve.

If you have them, show the high side and low side pressures as well as the compressor cycle time, this will help isolate your issue.