Forward/Stop/Reverse
A Number of Thoughts
by Bob Sundberg
Wheels of Distinction June 1997
BMW CAR Club of Hawaii
Cool(?) news about your BMW.... Unless you live in Saskatchewan, you probably know by now that the U.S. government (many other nations, too) is in the process of phasing out R-12 refrigerant ("Freon") in automotive air conditioners, as R-12 has been tagged as an ozone depleting substance. Since 199[X], BMW's new cars have been manufactured with air conditioning systems that only accept R-134 refrigerant - an "ozone-friendly" substance.
If your BMW was manufactured prior to 199[X], you probably know by now that it is becoming very expensive to keep the car's air conditioning system charged with R-12 refrigerant. This is completely in accord with the Government's plan to totally phase out R-12 refrigerant over the next few years. Owners of older BMWs can convert their auto air conditioning systems to R-134A, but there is a considerable expense involved. Substantial modifications to the existing system need to be made.
But there is an alternative to R-12 and R-134A. A company called Monroe Air Tech, Bloomington, Indiana, has developed a "R-406A" refrigerant that it is marketing under the trade name of "Autofrost" or "Autofrost X4."
R-406A refrigerant reportedly has a number of advantages over R-12 and R-134A. It is EPA-approved for use.- as an ozone-friendly" refrigerant - in both stationary and mobile (e.g., auto) air conditioning systems. R-406A can be substituted in an existing R-12 system, apparently with less modification required, than when changing over to R-134A. According to Monroe Air Tech, the receiving air conditioning system should have neoprene seals and O-rings, and use nylon lined "barrier" hoses (not older-style "nitrile" hoses). Neoprene products, according to Monroe Air Tech, are readily available through AC Delco and other distributors. "Barrier" hoses, have been used as standard equipment and as replacement hoses, for most cars for a number of years. "Newer" pre R-134A system cars may already have some of these components incorporated into their systems. R-12 system lubricants are generally completely compatible with R-406A, except for "PAG" oil, which is sometimes used to precharge replacement compressors. The only other special items required for R-406A are specially threaded fittings for the existing R-12 service ports on your car. This is a Federal requirement, apparently to prevent mixing of various refrigerants (especially R-12) in your auto air conditioning system.
R-406A costs less (reportedly less than half the cost) than R-12 refrigerant, although a bit more than R-134A. It only takes 80% of the amount of R-12 refrigerant for R-406A to charge a R-12 system. And Monroe Air Tech claims its R-406A refrigerant cools 10% more efficiently than R-12; 30% more efficiently than R-134!
There are some disadvantages known about R-406A refrigerant. Known leak detection equipment cannot detect R-406A, although the equipment can pick up lubrication (hydrocarbon) contamination present in the leaking R-406A. R-134A "HNBR" seals and O-rings are not compatible with R-406A refrigerant, complicating changing over from that system. More importantly, R-406A is not currently being distributed here in Hawaii. Monroe Air Tech reports that distributors are currently being established in Southern California, so presumably Hawaii distribution can't be far away.
Bottom line: If you have been thinking about changing over from R-12 to R-134A in you BMW's AC system, you may soon have a couple of options - hopefully making your choice less expensive.