Questions and Answers
R-12 To R-134a
Q. Hi Vincent, I recently had the A/C checked on my 1993 Honda Civic and had the evaporator, the expansion valve, and receiver dryer replaced. Then the system was fitted with new service ports and charged with R-134a.
It doesn't cool like it used to and I wonder if there is anything I can do to make the R-134a work properly in my car. I understand that just changing fittings over is not enough; a different condenser and other tricks are needed when a conversion is made. Any hints?
Thanks!
AlA. I've watched the switch from R-12 to R-134a over the years and at times it has been very difficult to separate fact from fiction. When R-134a was first introduced we got a bulletin saying that under no circumstances should R-12 and R-134a be mixed and you should not put R-134a into a R-12 system. If we did it would cause A/C compressor failure, A/C lines would start leaking and the world would come to an end. Well, now we are converting R-12 systems to R-134a and the world is still here.
The one cold hard fact is that R-134a is not as efficient as R-12. A R-134a system has a larger condenser and evaporator to bring it's performance up to R-12 performance. Since a conversion from a R-12 system to R-134a uses the smaller condenser and evaporator, you will notice a performance drop.
The parts they replaced on your car is about all they can do to bring the R-134a performance up to R-12 standards, assuming they used parts rated for R-134a. The only other modification they can do is to replace the A/C condenser with one that is 20 to 25% larger, then it would be just as cool as when it had R-12.
Additional Information provided courtesy of ALLDATA
