If your Miata is a ’95 or earlier, your air conditional system uses the old R-12 refrigerant which is getting very expensive and will only continue to do so because is hasn’t been manufactured in the U.S. since 1995.
The production of R-12 ended on December 31, 1995. The end of production has resulted in shortages and escalating R-12 prices.
However – there are now kits available to retrofit your old system to handle the new R-134a refrigerant. These kits cost as little as $50.
Retrofitting the system in your Miata protects you from high maintenance costs by outfitting your Miata a less expensive refrigerant.
Here is a list of what must be done to retrofit your system. This is NOT a how 'How-To' sheet on retrofitting – but just a guide to give you some idea what must be done. The bottom line is that it should not cost you a fortune to retrofit and if you have a leaky old system – the cost may be less then recharging you old R-12 system even once.
| 1. All R-12 refrigerant must be recovered by a certified refrigerant technician. Ask a service manager about this low-cost service. |
| 2. R-134a service port adapters must be installed and additional ports capped. |
| 3. A sticker identifying the system as having been converted must be installed on the under-hood air conditioning sticker. |
| 4. The accumulator/dryer or receiver/dryer must be replaced to acquire the correct desiccant for The R-134a refrigerant. |
| 5. An in-line filter must be installed if the compressor is replaced to prevent damage from residual debris in the system. |
| 6. Any R-12 mineral oil that is easily removed should be drained. The remaining mineral oil will not harm the system or performance of the system. |
| 7. Add four (4) ounces of Ester synthetic refrigerant oil to the system and the correct amount for any other replaced component in the system. |
| 8. R-134a molecules are a different structure than R-12 molecules and require a 10% reduction in the charge capacity (i.e. - a 30 oz R-12 system should be charged with 27 oz. of R-134a.) |
| 9. High-side pressures above 325 p.s.i.(very possible in some very hot climates) may require the installation of an electric pusher fan in front of the condenser at additional cost. The fan installation might be required and the requirement is generally unknown until completion of the job. |
Extra Charges:
The charges for the adapter fittings, stickers and Ester oil are the only extra cost when the conversion is done during major component replacement including accumulator or receiver/dryer. The difference in refrigerant prices between R-12 and R-134a will more than offset the additional cost in most cases.
