Automotive Air Conditioning Information Forum (Archives)

rickbrk on Thu July 15, 2010 12:49 AM

Year: 1986
Make: chevy
Model: c10
Engine Size: 305
Refrigerant Type: 134a
Ambient Temp: 90
Pressure Low: 35
Pressure High: 220

Not sure what is wrong after driving a few miles the a/c blows vapor out of the vents and a/c stops cooling. Is the evap freezing over? what are the causes for the vapor in the vents? Also how would I test the pressure or cycling switch that is on the accumulator?

Dougflas on Thu July 15, 2010 5:50 AM

Vapor can be normal if humidity is high. To test cycling switch, run engine at 1500 to 1800 rpm, put 20 inch window fan in front of grill, watch gauges for points of cycling. Follow test proceedures on this website. Sounds as if you're freezing up. In this case, keep windows closed as you want to get to point of max cooling to see if you can cycle on and off.

rickbrk on Thu July 15, 2010 3:27 PM

thank you for the input I will try it.