Automotive Air Conditioning Information Forum

I have mom's 92 Accord station wagon with 63,000 original miles. Car is in pretty good shape, except A/C doesn't work. I had R12 put in it a couple of years ago and it cooled well, until it leaked out. It was blowing 38F from the vents but it was dark and about 70 degrees when we finished at a guys shop and I drove it home. I didn't drive it for several months and the R12 escaped. Since R12 is pretty hard to come by, and some folks say a 134a conversion works well, I am looking into a conversion. Some folks also say R134A isn't as efficient when placed in a R12 system and it won't cool as well.

The 92 is an old car and as I recall the A/C didn't cool that well even when it was new. Probably because Honda didn't up-size the A/C system and just used the sedan system in a station wagon. The station wagon has a lot of greenhouse. Is it possible to convert this car to 134A today? Will it cool effectively up to 95-100 degrees F and 90% humidity? At one time I thought I'd need to change the compressor, the drier, the condenser, and all the hoses (to barrier type) but maybe not.

What do you guys with experience with this conversion have to say?

HotFatBoy needs A/C!

I'd have a professional shop find the leaks, repair them, and keep it R-12.

The system was originally designed for R-12, and cooling surely won't improve by converting it to R-134a, especially since you mentioned that it didn't cool sufficiently to begin with. In fact, you'll probably lose a bit of cooling capacity with a conversion, something you won't want to do with summer temps in the 90 to 100-degree range in your area.

Depending on the size of the leak and where it's leaking—it could be anywhere on a 28-year-old car—you might still have to flush the system and replace components, including the receiver/dryer, which should be changed anyway after opening the system. But if the car is in good shape and you plan to hold onto it for the foreseeable future, I recommend staying with the original R-12 refrigerant.

Thanks JohnHere. That was my plan but I called dozens of shops and none of them have the equipment any more to service R-12. Honda can't do it. I found a mechanic who had a few cans of R12 in his home shop, and I had a few in mine, and we were able to find the most egregious leak inititally (schrader valves). I can go back to him, but I think R12 is going to be the issue. I can probably find some R12 but it is expensive. I don't mind replacing hoses, etc to solve the leaks, but don't want to invest a lot of money for R12 if I'll ultimately have to switch to R134A. I can by the 134A compatible hoses if need be while working with R12, I think they are also compatible with R12, so no money really wasted there except they seem to be more expensive. I was hoping to find someone with experience with this particular model/era of Honda to provide some information on their experience with a conversion. At least I'll have a refrigerant that is readily available and shops all over the place that can then service the system.

Anyone have any experience with these older Honda's and converting them? Was the cooling capacity seriously diminished?

I have no direct experience converting a vehicle just like yours. But if you choose to go the conversion route, the system will have to be thoroughly flushed to remove all traces of the old mineral oil, replacing that with PAG or ester oil.

Components to flush include the evaporator, hard lines, and condenser, assuming the latter doesn't have debris from the compressor lodged in it and is a serpentine design. You might want to replace the condenser anyway with a more efficient parallel-flow unit if available. If not, then an original-style unit will have to do.

If the 28-year-old compressor appears to be leaking at the shaft seal (and even if it's not), I would replace it with a new OEM unit. A receiver/dryer containing desiccant compatible with R-134a must be installed. I would also change the TXV, the hoses (barrier style), as well as all the o-rings.

A professional conversion will be expensive but should result in a leak-free system, which then can be evacuated and recharged to about 85 percent of the original R-12 amount. However, cooling probably still won't be quite as good as keeping it R-12.

Well, JohnHere, that is my understanding as well, that an R12 system that has been converted to R134A won't cool as well. It doubly concerns me since my impression is that the Honda A/Cs of that vintage didn't cool as well as the American Big 3 manufacturers A/Cs, and triply concerns me since this car is a station wagon. Thus the reason why I'm searching for real-life experiences. All the shops around here (Maryland) want to convert it, but they don't have to ride around in the car afterwards, I do. I know it can be converted, but I'm trying to determine if it should be converted.

I've read some of the other posts and topics and several people suggest keeping the systems as R12. Like there is a number of shops that can service the R12 system. My question would be then, where are they suggesting a person turn to for service work, and where does one find R12 from a trustworthy source?

Hopefully, an expert on this forum having first-hand knowledge of converting the same or similar vehicle you have will see this thread and offer advice.

Earlier, you alluded to an acquaintance who helped you re-charge the system with the original refrigerant. Unfortunately, that re-charge didn't last. Since you haven't been able to find another shop willing and able to service the system with R-12, perhaps he or she would once again offer the tools and expertise to help you repair the system yourselves—that is, replace components, fix the leaks, and recharge it.

The refrigerant is still available from a number of online sources—NAPA and Refrigerant Depot, for instance—although it is expensive and you'll need an EPA 609 Certification to purchase it. Once the system is fixed and leak-free, though, you should be good for many more years of trouble-free operation, eliminating the need for occasional service by a local shop.

If you find it virtually impossible to have the system restored locally with R-12, I would go ahead and convert it to readily available R-134a even though the system's performance most likely will be somewhat diminished. Some cooling is better than none, and at least you'll be able to drive the car during the warm weather months.

I forgot to mention that I would definitely stay away from the alternative hydrocarbon-based refrigerants containing propane, isobutane, and the like, especially when R-134a is still readily available.