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Old 09-01-2015, 10:55 PM
Robinls5 Robinls5 is offline
Junior Member
Join Date: Jun 2015
Posts: 9
Default A/C conversion

First,,If you have R-12 and it is working........ Keep It.....
To convert to R-134 in a Chevelle. You need to change "" 2 "" items.
1--Have your POA valve adjusted for R-134.
2--If you want to have the SAME TEMP. as a late model auto.
I would change to a paralell flow condenser, WHY? R-134 Builds up more heat than R-12. SO,, The old style round Appx. 3/8" dia. tubes. The difference is,, The old round stock org. Condenser does not have enough Sq. In. of cooling surface to cool down R-134. NOTE: If you can keep you Chevelle moving at 35 MPH. or above, The condenser will recieve enough air over the tubes to keep you at 43 degrees. Under 35 MPH a 60s-70s stock condenser is not efficient.
My 70 Sta. Wgn. SS468 driver blows 43 degrees out the center vent at ALL TIMES when the A/C is operating. ( Parked in the sun on a hot day or driving on the I-State).
A 1970 C-60 A/C calls for a 60 Oz. charge. I use the 80% rule for R-134. I charce my R-12 60 OZ. system with 48 OZs. of R-134.
The ONLY "" 2 "" items you need to change are 1= POA adjusted fo R-134.... # 2 For good cooling I would change from the factory TUBE cond. to a P. Flow condenser.
P.S. If you get an Aftermarket A/C unit you will be using a P. Flow Condenser.
The G.M. unit in your car is BETTER than ANY aftermarket unit that money can buy. BAR NONE !
I would stick with a O.E.M. unit if possible.
Again being KOOL is not cheep !
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