My ac hasn't been working for some time, I checked the pressure on the low side it was roughtly 0 psi. I started adding more r-134a to the system through the low pressure port with the car running. As I was doing this the compressor seemed to be trying to kick in as the pressure came up but it seemed to come on and off very quickly. Also I looked down and it didn't seem like the pulley was spinning with the ac on however the inner part started spinning as soon as it kicks off. Can I assume the compressor is done?

 

Did you give it a full charge? What is the static pressure?

 

Nope not a full charge, I stopped once I noticed that the pulley didn't seem to be spinning when it did kick on.

 

well IM not sure what the pressure has to be, but the pressure switch is like a safety switch. it will not allow the clutch to engage if the pressure is below a certain threshold. give it a full charge and see what happens.

but my old pump would interm. sieze when I tried to use it. the belt would start squealing VERY loudly immediatly when I turned the a/c on sometimes. finally everytime I tried to use it so I replaced the pump.

 

I added some more r-134a today, at second glance I think the pulley is spinning. However I notice when the compressor tries to kick on the pressure drops from about 20psi to 0psi and then back up. With the A/C off its at about 40-50psi and with the car off around 70psi.

 

Shoebox has an AC performance chart on his site - maybe it's just low? Static pressure for the LS1 is about 100 psi. http://shbox.com/1/ac_performance_chart.jpg

 

The pressure does seem a little low but I have put enough r-134a in that it should be coming on? Anyone know how much it should hold? also something about the quick on and off of the compressor just doesn't sound right.

 

Turns out I didn't have enough in there for the compressor to stay on. I added some more today and shes blowing ice cold.