How to Mix R134A with R12
R-12 freon and R-134 freon cannot be mixed or used in the same system, but an existing R-12 system can be converted to an R-134 system. Convert your vehicle's air conditioning to R-134 to save money; R-12 is extremely expensive and can only be recovered and recharged by a certified professional. No vehicle produced in the United States has used an R-12 system since production of the freon was stopped in 1995.
Any R-12 remaining in your car must be recovered by a certified professional using a specialized recovery machine that prevents leaks into the atmosphere. It is illegal to handle R-12 freon without a license.
A retrofit R-134 service port must usually be installed before the system can be recharged with R-134 freon. To do this, simply place the new service ports over the existing R-12 ports and tighten to 20 foot-pounds of torque.
Attach the recharge service hose on your car's air conditioning system to the low pressure gauge. With the can held vertically, open the valve to release the air from the hose. Close the valve and the hose will fill with freon.
Turn your car on and turn the air conditioner to maximum power. Fasten the freon-filled hose to the air conditioner's service fitting and open the valve. Fill the system to 40 psi and close the valve.
- Refer to the vehicle's manual for the amount of R-12 required and purchase 90 percent of this amount in R-134. It takes approximately 10 percent less R-134 than R-12 freon.
Leah Newman has been a professional writer since 1999, writing about fine arts both in print and online. She specializes in how-to articles covering DIY projects. Newman holds a Bachelor of Arts in English from the University of Georgia and a Graduate Certificate in Children's Literature from Pennsylvania State University.
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