My air conditioner compressor is working and building lots of pressure on the high pressure side, but there is no pressure on the low side. I had it working ok with just barely cold air coming out for about 30 miles and then the pressure built up and the excess pressure was being forced out of the compressor and I could hear it releasing while driving. I replaced the drier, and the low pressure hose on the front has no blockage. The compressor also seems to never disengage when I run the A/C. Thanks!

 

Did you pull a vacuum before you refilled the system?

 

Sure did!

 

You have a blockage or may have a expansion valve failed close, causing too high, high side pressures.

Suggest discharging system and air-blasting condensor and hoses to check for any obstructions. If condensor is blocked, replacement is indicated.

Remove evaporator and replace expansion valve. Check that evaporator is not blocked. Replace all orings on expansion valve and thermo-feedback bulbs.

Don't leave receiver/drier open to atmosphere. Plug w/ something.

Reassemble w/ new orings on all connections, after installing 5-7 oz of PAG or Ester lubricant in compressor and receiver/drier. Check ackits.com for double-end capped PAG or Ester oil.

Vacuum for at least 1/2 hr and recharge w/ prescribed weight of R134a.

good luck