A/C: Converting To 134A

Upgrades: Keep it Cool! strongConverting to 134astrongbr Courtesy of Classic Auto Air a href"http:www.classicautoair.com"Classicautoair.comabr Until 1995, most cars with air conditioning used R-12 Freon refrigerant that is said to have a negative side effect of damaging the ozone layer and is no longer in most countries. Now, the industry standard is R-134a, which is an efficient absorber and carrier of heat without the ozone layer-damaging issues of R-12. Contrary to belief, most cars originally equipped with R-12 can be converted to 134a and still keep you just as cool. Recommended steps to converting your GM R12 air conditioning system to 134a: strong1955-61 Models with Hot Gas Valve (aka Bypass or Hot Gas Bypass Valve)strongbr The Hot Gas Valve is most often found mounted to the compressor, though some cars have it mounted back near the evaporator. The front half of it looks like a bullet. a href"http:blog.ecklerscorvette.comwp-contentuploads201505Valve-59-60CadHGVAfter2.jpg"img class"alignnone size-medium wp-image-2126" src"http:blog.ecklerscorvette.comwp-contentuploads201505Valve-59-60CadHGVAfter2-300x199.jpg" alt"Valve-59-60CadHGVAfter2" "300" height"199" abr strongemMinimum Requirementsemstrongbr or restore the filter-drier.liululppululliDrain the compressor oil and recharge with 134a compatible oil. (PAG or Ester Oil)liululppululliEnsure that the system is clean and free of contaminants (Depending on component condition, this may be a simple matter of blowing out with compressed air or liquid flushing with an air conditioning flushing agent)liululppululliReplace or restore all rubber hoses with barrier hose.liululppululliRebuild hot gas valve.liululppululliInstall 134a charge adapters.liululppululliCharge with 134a between 70-80 of the original R12 charge amount. Note: Hot gas valve will need to be adjusted during the charging to adjust the low side bypass to 20psi.liululppululliReplace any o-rings with 134a compatible.liululpbr strongem emstrongstrongemRecommended:emstrongbr hilo switchliululpbr strongem emstrongstrongemHelpful hints:emstrongbr the sight-glass. A charged 134a system will likely show bubbles in the sight-glass.liululppululliTypical 134a charge rate will be approximately 70-80 of the factory R12 charge amount.liululpbr strong1962-66 Models with Suction Throttling Valve (aka STV)strongbr The suction throttling valve is installed on the evaporator, near the firewall. a href"http:blog.ecklerscorvette.comwp-contentuploads20150563-66CorvetteSTVAfter.jpg"img class"alignnone size-medium wp-image-2127" src"http:blog.ecklerscorvette.comwp-contentuploads20150563-66CorvetteSTVAfter-300x239.jpg" alt"63-66CorvetteSTVAfter" "300" height"239" abr strongem emstrongstrongemMinimum Requirementsemstrongbr or restore the filter-drier.liululppululliDrain the compressor oil and recharge with 134a compatible oil. (PAG or Ester Oil)liululppululliEnsure that the system is clean and free of contaminants (Depending on component condition, this may be a simple matter of blowing out with compressed air or liquid flushing with an air conditioning flushing agent)liululppululliReplace or restore all rubber hoses with barrier hose.liululppululliRebuild suction throttling valve.liululppululliInstall 134a charge adapters.liululppululliCharge with 134a between 70-80 of the original R12 charge amount. Note: Suction throttling valve will need to be adjusted during the charging to adjust the low side bypass to 20psi.liululppululliReplace any o-rings with 134a compatible.liululpbr strongem emstrongstrongemRecommended:emstrongbr hilo switchliululpbr strongem emstrongstrongemHelpful hints:emstrongbr the sight-glass. A charged 134a system will likely show bubbles in the sight-glass.liululppululliTypical 134a charge rate will be approximately 70-80 of the factory R12 charge amount.liululpbr strong1966-73 Models with POA Valvestrongbr The POA Valve is installed on the evaporator, near the firewall. a href"http:blog.ecklerscorvette.comwp-contentuploads201505VALVE-POAValveAfter15-52.jpg"img class"alignnone size-medium wp-image-2128" src"http:blog.ecklerscorvette.comwp-contentuploads201505VALVE-POAValveAfter15-52-261x300.jpg" alt"VALVE-POAValveAfter15-52" "261" height"300" abr strongemMinimum Requirementsemstrongbr or restore the filter-drier.liululppululliDrain the compressor oil and recharge with 134a compatible oil. (PAG or Ester Oil)liululppululliEnsure that the system is clean and free of contaminants (Depending on component condition, this may be a simple matter of blowing out with compressed air or liquid flushing with an air conditioning flushing agent)liululppululliReplace or restore all rubber hoses with barrier hose.liululppululliInstall 134a charge adapters.liululppululliSend POA valve in to be calibratedliululppululliCharge with 134a between 70-80 of the original R12 charge amount.liululppululliReplace any o-rings with 134a compatible.liululpbr strongem emstrongstrongemRecommended:emstrongbr hilo switchliululpbr strongem emstrongstrongemHelpful hints:emstrongbr the sight-glass. A charged 134a system will likely show bubbles in the sight-glass.liululppululliTypical 134a charge rate will be approximately 70-80 of the factory R12 charge amount.liululpbr strong1973-76 Models with VIRstrongbr The VIR is installed on the evaporator, near the firewall. a href"http:blog.ecklerscorvette.comwp-contentuploads201505VALVE-VIRAfter.jpg"img class"alignnone size-medium wp-image-2129" src"http:blog.ecklerscorvette.comwp-contentuploads201505VALVE-VIRAfter-266x300.jpg" alt"VALVE-VIRAfter" "266" height"300" abr strong strongstrongemMinimum Requirementsemstrongbr desiccant in VIR.liululppululliDrain the compressor oil and recharge with 134a compatible oil. (PAG or Ester Oil)liululppululliEnsure that the system is clean and free of contaminants (Depending on component condition, this may be a simple matter of blowing out with compressed air or liquid flushing with an air conditioning flushing agent)liululppululliReplace or restore all rubber hoses with barrier hose.liululppululliInstall 134a charge adapters.liululppululliCharge with 134a between 70-80 of the original R12 charge amount.liululppululliReplace any o-rings with 134a compatible.liululpbr strongem emstrongstrongemRecommended:emstrongbr hilo switchliululppululliInstall our VIR Eliminator (strongly recommended when converting to 134a), a rebuilt VIR or let us, Classic Auto Air, rebuild yours.liululpbr strongem emstrongstrongemHelpful hints:emstrongbr the sight-glass. A charged 134a system will likely show bubbles in the sight-glass.liululppululliTypical 134a charge rate will be approximately 70-80 of the factory R12 charge amount.liululpbr strong1977-94 Models with Accumulatorstrongbr The accumulator is most often installed on the evaporator, near the firewall. a href"http:blog.ecklerscorvette.comwp-contentuploads201505Accumulator1.jpg"img class"alignnone size-medium wp-image-2133" src"http:blog.ecklerscorvette.comwp-contentuploads201505Accumulator1-300x272.jpg" alt"Accumulator" "300" height"272" abr strongemMinimum Requirementsemstrongbr or restore the accumulator.liululppululliDrain the compressor oil and recharge with 134a compatible oil. (PAG or Ester Oil)liululppululliEnsure that the system is clean and free of contaminants (Depending on component condition, this may be a simple matter of blowing out with compressed air or liquid flushing with an air conditioning flushing agent)liululppululliReplace or restore all rubber hoses with barrier hose.liululppululliInstall 134a charge adapters.liululppululliCharge with 134a between 70-80 of the original R12 charge amount.liululppululliReplace any o-rings with 134a compatible.liululpbr strongem emstrongstrongemRecommended:emstrongbr hilo switchliululppululliUpgrade the standard orifice-tube to a variable orifice tube.liululpbr strongem emstrongstrongemHelpful hints:emstrongbr the sight-glass. A charged 134a system will likely show bubbles in the sight-glass.liululppululliTypical 134a charge rate will be approximately 70-80 of the factory R12 charge amount.liulul