how many ounces of R134A to add to a C3 Corvette with a retrofitted system

[Christopher R.]

I have retrofitted the R12 system and converted it to a R134A but I still have the original factory compressor. All of the support i have seen says you don't need as much R134a as stated on the R12 sticker. Anyone have an idea of how many ounces to put in from a dry system?

[Harmon C.]

Re: how many ounces of R134A to add to a C3 Corvette with a retrofitted system

May not help but just changed the 134 in my truck and it took 1# 6 oz.

[Jim T.]

Re: how many ounces of R134A to add to a C3 Corvette with a retrofitted system

Lyle, My 1996 Corvette lists 2 pounds of 134 to charge the air conditioning system on my 1996 Corvette. My 1970 Corvette with factory air the use capacity is listed at 3 pounds and 4 ounces.

[Joe C.]

Re: how many ounces of R134A to add to a C3 Corvette with a retrofitted system

I have retrofitted the R12 system and converted it to a R134A but I still have the original factory compressor. All of the support i have seen says you don't need as much R134a as stated on the R12 sticker. Anyone have an idea of how many ounces to put in from a dry system?

A Google search yielded the standard rule of thumb as .8 lb 134a for each pound of R12 originally used to fill the original system

http://www.peachparts.com/shopforum/tech-help/123399-one-pound-r12%3Dhow-many-pounds-r134a.html

[Reiner O.]

Re: how many ounces of R134A to add to a C3 Corvette with a retrofitted system

As Joe said, I own a repair facility and back when we did a bizilloin R134 conversions the manufacturers recommended 80% of the R12 charge

[Robert B.]

Re: how many ounces of R134A to add to a C3 Corvette with a retrofitted system

The 80% is a good number but if you are using manifold gauges (and I hope you are) pay more attention to the pressure readings than the weight. Get a chart for your application and charge to that. Likely that you will be right about at the 80% number when done.