Automotive Air Conditioning Information Forum

OK...just want to give an update. I have been doing diagnostics with the help of a "corvette mechanic and friend". With his help, we found the Blower Control Module to be defective. Compressor is now running. I turned the compressor off and on a dozen times to burnish the hub and pulley face of the ...

swampy 6x6
hi
Always start with 90% going from R12 to R134a then charge according to
pressures high /low expected for the system
low around avg 28psi
high side no more than 250psi but lower below 200 is ideal . If high side is around the 250 psi really needs more condenser and or fan
txv system ...

Does anyone know anything about the triangle shaped stamp on the GM R4 compressor body? Does it signify anything, polarity?

Tim

We're talking about a Vette here with an accumulator. The inlet and outlet on the evap should be close in temp. So charge to 80% and feel the difference. Slowly add more until they feel the same.

Thanks.Wanna buy a vette?

tbirdtbird

Just FYI, the 80% number is not hard and fast...it may require closer to 90% to properly function. Bottom line, start with 80% and add from there as needed.

Yes, I had heard that and that was my plan. Thanks.

JohnHere
Kenny, it might be worth calling your local Chevrolet service department to see what they can tell you.

I called several and none can go back to 1986. They are all relying on ALLDATA. They polly know more about UFOs than the 86 Corvette.
So I am going with my GM Service Manual...which ...

Thanks Tim. I am doing diagnostics on the bcm also

I will call my local Chevy dealer tomorrow

My FSM agrees with Tim. 80% of 2 3/4 lbs

tbirdtbird
Your 9 pp has gone on for so long I really have no idea what has been done or even what was wrong.

Long story short:
I converted my 86 vette over to 134a. I replaced ALL components of the original AC syatem but the Evaporator tube/liquid line. I also installed a new parallel flow ...