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1968 Buich 134a Conversion

John Eberly on Sat April 30, 2011 1:07 PM User is offline

Year: 1968
Make: Buick
Model: GS400
Engine Size: 400
Refrigerant Type: 134a
Ambient Temp: 60F
Pressure Low: 35
Pressure High: 50
Country of Origin: United States

Strange pressures and little cooling after retrofit - what components to check?

All original components except new receiver/dryer.
System was open for several years
System flushed and blown out
Compressor flushed with DEC PAG, compressor pumped oil when turned over
New o-rings
New reciever/dryer
POA adjusted to 26 psi
System held test pressure for two days and vacuum for two days

Manufacturer's literature calls for 4.25 lbs of R12.
Charged one 12 oz can at a time until 60 oz added.
Jumped compressor clutch to get compressor to run
High side pressure never came up beyond 70 psi and only reads 50 psi with current charge
Lowest vent temp was 56-57 degrees

Suspect expansion valve may be plugged?
Please advise on troubleshooting procedure.

Dougflas on Sat April 30, 2011 3:01 PM User is offline

Is the high side handwheel closed? To check the TXV, remove the bulb and hold it in your hand. The Place it in ice water bath. You should see the TXV open and close.

Go to the proceedure section and follow the testing of Chrysler ERP systems. Basically the POA and EPR do the same thing. There is a section on testing the TXV

Edited: Sat April 30, 2011 at 3:03 PM by Dougflas

John Eberly on Sat April 30, 2011 9:47 PM User is offline

Thanks, I will do that.

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