Jon8903

Try to refrain from jokes about popping off too early...

After resetting the PCM to get the compressor to finally come on in my 95 Z28, the mechanic hooked up a can of R134 to charge the system only to have the blow off valve engage around 220/30 on the high/low side. He said that valve should not have popped off until around 400 psi.

The radiator fans are engaging now and the system is blowing slightly cool air but it's obviously not running like it should. He advised I contact the eBay seller I bought the compressor from and try to get a refund. I guess I need to shop around for a new compressor and drier and try to get my money back for the old one.

Is there something I'm missing? Something else that could be causing that blow off even though the gauges don't indicate a high pressure situation?

Thanks

bobdec

High pressure relief valve should hold till 440 lbs. If the manifold was reading 230 the relief valve is defective, something internal to the compressor is defective, or a blockage between the compressor high output and the high side test port and the only things in that path are the ac line to condenser, and the condenser coil which has very small passage ways, did your old compressor throw off debris when it went out ?? . Ref shbox.com http://shbox.com/1/ac_system.jpg # 1 for condenser # 29 for AC line , # 5 is high test port and for clarification items #'s 36-38 should not be in the pic, there is no low side sensor on F-Bodys. If the condenser is the cause GM does not recommend backflushing the condenser, it's a manifold design where backflush fluid will flow through the open lines and still may not clear debris in the clogged lines. Since you have 230 lbs at test point again if it is the condenser it's not completely blocked.