R12 after October 2000

Now that R12 is now longer available we need to look at what has to be done when it is time to recharge the system. If your car has the earlier refrigerant R12 or Freon (basically prior to 1993) and you feel that it is time to recharge the system let's stop and consider the options.
1. The AC is still working reasonably but it is 3 years since it was last recharged and surely it must need a recharge now
2. The AC is hardly working with little cooling or has stopped completely.
Let's cover the first one - number 1. Ignore all my exhortations in the paragraphs above about 3 yearly recharges and hang on to the remainder of the R12 that you have. The alternatives are not as good as R12 so wait until the system is noticeably not cooling as it should and then go on to number 2.
Once you get to number 2. there are several options available probably with your AC technician's advice but broadly here is the scenario. If the system has stopped working because of a perhaps a compressor failure, perhaps the best solution is that when the compressor is replaced, also replace the drier and retrofit with the later R134a refrigerant. In many cases a drop in performance may be noticed but should still be acceptable. A few compressors used on early classic cars are unable to use R134a, it is also worth looking at the rest of the rubber hoses as some of the earlier ones are unsuitable for R134a and would need replacing with more modern hoses.
Even if the compressor is not being replaced it may be worth considering retrofitting to R134a if the compressor type is capable of handling the higher pressures required - your AC technician will know. You may also consider changing a perfectly performing R12 only compressor for a new compressor which is able to handle R134a, many of which are identical in size and configuration and can fit directly on to the car.
In all cases of retrofitting to R134a the oil in the system would need to be changed but the technicalities of the oil type and the extent and type of the change are beyond the scope of this article.
The other real alternative is to have the remaining R12 recovered and use one of the 'drop-in' replacement refrigerants for R12 that have been approved for automotive use. Again a replacement drier may be prudent together with the addition of a small amount of a synthetic compressor oil. The performance should in most cases approach that of R12, the loss may not be noticeable. At the moment all the evidence suggests that these replacement refrigerants would need recharging at slightly more frequent intervals than R12, as the risk of compressor damage would appear to be greater as the charge gets low than it was with R12.
The details of the law on R12 after January 2001 appear to have been written by someone with little appreciation of the real world out there but maybe someone will revise it with a little common sense. Oh look, there goes another herd of pigs flying past.
I feel that a little update might be appropriate on this matter nearly two years after the removal of R12. As at September 2002 we have now treated very many cars that were previously R12 systems. The vast majority of these have been given a refrigerant that is not a mixture of gasses as are some of the drop-in replacements but is basically the latest refrigerant R134a together with additives to ensure that the refrigerant carries the existing lubricant around correctly. In theory at least the system should be slightly less effective than with R12 but I am happy to report that in practice I can see no difference with the performance of the alternative refrigerant
Update in late 2005 – Many of the fears we had in the early days of changing older R12 systems onto the drop-in replacements or R134a now seem relatively insignificant. Early cars sometimes have hoses which are not completely impervious to R134a, these can sometimes be changed but where it is not really possible the reality is frequently that the loss is fairly inconsequential anyway. In theory some of the early compressors not designed for R134a would not work correctly with the new refrigerant but in practice seem to cope adequately. It all depends on the car owner’s attitude – whether it is just an elderly car which is going perfectly but in need of a breath of fresh gas or whether it is a much loved and pampered expensive passion.

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