1986 Corvette R-12 to R-134a Conversion

[kenlou]

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

[kenlou]

I will call my local Chevy dealer tomorrow

[Tim]

The higher capacity listing is most likely for an A6 compressor, which this does not have. Also, there is or was enough refrigerant to engage the clutch if "All" the electrical was operating correctly. Jumping the clutch coil only provides data for a single system component.

The data I posted came from ALLData, 2023

[kenlou]

Thanks Tim. I am doing diagnostics on the bcm also

[kenlou]

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 states 2 3/4 lbs R-12....which translates to 36 oz of R134 (80% amount of original R-12).

[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. Somewhere in the archives here is a procedure for charging an unknown system posted by bohica (Brad)

[kenlou]

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.

[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.

[kenlou]

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?

[kenlou]

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