1985-1992 Fleetwood, 1993 Sixty Special, All FWD Forum Discussion, R12 To 134a Conversion in Past Cadillac Vehicle Discussion; just changed the a/c over to r134a what should the low and high pressure on the gages read ?? sticker ...
- 07-05-04 10:17 PM #1Cadillac Owners Member
- Join Date
- Jul 2004
R12 To 134a Conversion
just changed the a/c over to r134a what should the low and high pressure on the gages read ?? sticker says it takes 3.75 pounds and i only put in 36 oz so far ,need a little info on this .high side showing 170 at a idle.and 40 on the low side .
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- 07-05-04 10:25 PM #2
Re: R12 To 134a Conversion
Charge the system with the same amount of R134a as was spec'd for R12. There is a mistaken belief that R134a should be charged to a lower level than was spec'd for R12 when a conversion is done. To make the system cool correctly and make the low refrigerant diagnostic codes work correctly the GM systems must be charged to the same level whether it is R12 or R134a.
You really can't go by the low and high side pressures as they are far too variable on an automotive system depending on the ambient, load on the system, etc... Just charge it to the correct level as specified. No guessing that way.
Did you install a new accumulator when you did the conversion? That is one of the keys to making the R134a converision successful. A fresh dessicant charge is required with the R134a and the only way to get that is to install a new accumulator.