My daily driver is an old '93 Toyota Corolla. It has the original A/C coolant in it, but it needs to be recharged. I know the correct thing to do is to suck the old R-12 coolant out and introduce hard vacuum before adding R134a. But can I simply add R134a on top of what's already in there? Or were Toyotas already using R134a in '93? I really don't want to dump a ton of money into a car I paid $200 for. Also, I've never recharged an A/C before, so this would be my first time.
'93 was a transitional period, so I'm not sure what your car would have in it, but you cannot put 134 in to top it off if you have 12 in it now. At a minimum, you need to reclaim the 12, drain the oil out, change the o-rings to a buna-n type, refill with PAG or ester oil, and then charge with 134. Again, that's the minimum.
bravenrace wrote: '93 was a transitional period, so I'm not sure what your car would have in it, but you cannot put 134 in to top it off if you have 12 in it now. At a minimum, you need to reclaim the 12, drain the oil out, change the o-rings to a buna-n type, refill with PAG or ester oil, and then charge with 134. Again, that's the minimum.
Dang, that sounds like way too much work. I'm going to check tonight if the thing already has R134a.
For a $200 car, maybe it would be worth trying the Freeze-12 or other R12 compatible stuff? Worst case you bust the a/c worse.
Hey, I'm in the middle of doing that swap right now. Short answer, yeah, to do it correctly costs a few bucks: pull out the old fluid, change O-rings, flush the compressor, etc. I also had to change the drier.
dculberson wrote: For a $200 car, maybe it would be worth trying the Freeze-12 or other R12 compatible stuff? Worst case you bust the a/c worse.
+1
bravenrace wrote: '93 was a transitional period, so I'm not sure what your car would have in it, but you cannot put 134 in to top it off if you have 12 in it now. At a minimum, you need to reclaim the 12, drain the oil out, change the o-rings to a buna-n type, refill with PAG or ester oil, and then charge with 134. Again, that's the minimum.
I cheaped out on my 92 Achieva and put R134 into the empty R12 system, without changing anything (I did mention I was being real cheap?). It worked pretty good for a bit more than a year. Compressor started making a bit more noise (compressor was going to have to be changed eventually anyways) but was still cooling when I traded the car in. Maybe I was just lucky.
dculberson wrote: For a $200 car, maybe it would be worth trying the Freeze-12 or other R12 compatible stuff? Worst case you bust the a/c worse.
That's what I'd do - there are refrigerants made for putting in R12 systems without evacuating them.
81cpcamaro wrote:bravenrace wrote: '93 was a transitional period, so I'm not sure what your car would have in it, but you cannot put 134 in to top it off if you have 12 in it now. At a minimum, you need to reclaim the 12, drain the oil out, change the o-rings to a buna-n type, refill with PAG or ester oil, and then charge with 134. Again, that's the minimum.I cheaped out on my 92 Achieva and put R134 into the empty R12 system, without changing anything (I did mention I was being real cheap?). It worked pretty good for a bit more than a year. Compressor started making a bit more noise (compressor was going to have to be changed eventually anyways) but was still cooling when I traded the car in. Maybe I was just lucky.
The biggest problem with doing that is that 134 reacts with the mineral oil in 12 systems and eventually kills the compressor, sending little bits of metal all through the system. Yes, you got lucky.
Judging by the various R12 to R134 conversions I and friends have done over the years, and the many years of service we've both gotten out of some we did on our own cars, I'm real comfortable saying the claims of self destruction are overblown. Suck it down, add the kit, and go on along.
The OP question almost reads like: "can I top off an R12 system with R134?" In that case, I simply don't know. I don't know if anyone actually knows. Reading around on the always infalable web you see dire proclamations of death and goo in the system, should you do this. But never by folk who've actually done it, they just somehow know this is what will happen. And a sprinkling of posts from guys who don't seem swift claiming they've done it. Usually to a car they promptly get rid of.
If it were my car, and I found out for sure it had R12 in it (the fittings will usually tell you), I'd probably get a can of fake R12 and use that to top it back off. If I found it was converted (again, the fittings), I'd top it off with a can of R134.
bravenrace wrote: The biggest problem with doing that is that 134 reacts with the mineral oil in 12 systems and eventually kills the compressor, sending little bits of metal all through the system. Yes, you got lucky.
I can vouch for this. Seized the compressor in my wife's Accord doing this. It was my first a/c retrofit and the kit I bought didn't mention changing out the oil. It's not a good idea to run R134a in an R12 system without changing the oil.
foxtrapper wrote: Judging by the various R12 to R134 conversions I and friends have done over the years, and the many years of service we've both gotten out of some we did on our own cars, I'm real comfortable saying the claims of self destruction are overblown. Suck it down, add the kit, and go on along. The OP question almost reads like: "can I top off an R12 system with R134?" In that case, I simply don't know. I don't know if anyone actually knows. Reading around on the always infalable web you see dire proclamations of death and goo in the system, should you do this. But never by folk who've actually done it, they just somehow know this is what will happen. And a sprinkling of posts from guys who don't seem swift claiming they've done it. Usually to a car they promptly get rid of. If it were my car, and I found out for sure it had R12 in it (the fittings will usually tell you), I'd probably get a can of fake R12 and use that to top it back off. If I found it was converted (again, the fittings), I'd top it off with a can of R134.
I didn't realize the fittings were different and that there is R-12 compatible refrigerant available. Does anyone have pictures of what the different fittings look like?
In reply to Sky_Render:
There a lot of things people do and get away with that aren't necessarily correct, like foxtrapper above. There is really only one correct way of doing a conversion, and that would necessitate changing virtually every component, which defeats the purpose. But 134 and 12 systems operate differently and require different designs. Any conversion is a compromise. So the question is, how much do you compromise? My question to you would be how long do you want it to last, and when the compressor locks up, are you going to want to repair it? If your answer is yes, then you need to do the conversion the best way you can that makes sense for you, because once the compressor spreads metal shavings all through your A/C system, it will never be the same and you will wish you took the extra step to flush the mineral oil out of it. I don't have any pictures handy, but in automotive, R-12 system charge ports have a shrader valve similar to a tire valve, and 134 systems have quick disconnects that look similar to a compressed air line quick disconnect. If you do a conversion, you can get adapters that screw on to the shrader valve ports, but be careful because I've seen many of these cause leaks. Officially, there is no adequate R-12 substitute other than 134. That said, there are many non-official substitutes, and some are better than others. Many of them are merely propane. Most are highly flammable. Use at your own risk.
I've been very happy with Enviro-Safe in two different cars.
But I've never topped off with it.
Don't forget, it only takes a $25 online test to get EPA certified. You can then buy just a can of R12 and top it off.
So I wonder if my alternator could power an inverter that lets me put a window A/C unit in the hatchback...
Try propane.
bravenrace wrote:81cpcamaro wrote:The biggest problem with doing that is that 134 reacts with the mineral oil in 12 systems and eventually kills the compressor, sending little bits of metal all through the system. Yes, you got lucky.bravenrace wrote: '93 was a transitional period, so I'm not sure what your car would have in it, but you cannot put 134 in to top it off if you have 12 in it now. At a minimum, you need to reclaim the 12, drain the oil out, change the o-rings to a buna-n type, refill with PAG or ester oil, and then charge with 134. Again, that's the minimum.I cheaped out on my 92 Achieva and put R134 into the empty R12 system, without changing anything (I did mention I was being real cheap?). It worked pretty good for a bit more than a year. Compressor started making a bit more noise (compressor was going to have to be changed eventually anyways) but was still cooling when I traded the car in. Maybe I was just lucky.
Yep, quite lucky. I knew the compressor was going to have to be changed eventually so I did it just to see what would happen. The few other R134 conversions I have done have been properly with new compressors and all the right stuff. They worked perfectly. If I had kept that car it probably would have ended up with the a/c removed anyways. Almost started turning it into a prepared autox car, it was already a DSP car (it was a W41 car).
Sky_Render wrote: I didn't realize the fittings were different and that there is R-12 compatible refrigerant available. Does anyone have pictures of what the different fittings look like?
R12. Conventional looking valve stem, just like your bicycle or car tire.
R134 conversion fittings. These screw onto the old R12 fittings.
Caviat. Lots of R134 kits have lousy fitting,and they aren't always installed. If you've got the kits and or manifolds for both R12 and R134 you can easil fill either type of fitting with either type of gas.
I actually just ordered some refrigerant from Enviro-Safe earlier this week. Decided not to go with Freeze-12 because it’s just a mix of 134A and 142 and will most likely just leak out through my R12 hoses and seals since it’s a smaller molecule. Yeah Enviro-Safe is a Hydrocarbon refrigerant but that doesn’t bother me. Hopefully it will be here by this weekend and I can give you some more feedback once its in. Read up on it and see if it’s a good option for you.
http://www.es-refrigerants.com/products/w/id/14/t/refrigerant
PseudoSport wrote: I actually just ordered some refrigerant from Enviro-Safe earlier this week. Decided not to go with Freeze-12 because it’s just a mix of 134A and 142 and will most likely just leak out through my R12 hoses and seals since it’s a smaller molecule. Yeah Enviro-Safe is a Hydrocarbon refrigerant but that doesn’t bother me. Hopefully it will be here by this weekend and I can give you some more feedback once its in. Read up on it and see if it’s a good option for you. http://www.es-refrigerants.com/products/w/id/14/t/refrigerant
Looks good! Are any special tools required besides what's included in this kit?
http://www.es-refrigerants.com/products/w/id/481/t/r12-substitute-super-seal-ac-recharge-kit/details.asp
I'd borrow/rent a vacuum and gauges from AdvanceOriellyPepZone and pull a good deep vacuum on the system.
Enviro-Safe actually says not to pull a vacuum on the system. I think their reasoning is that HC based refrigerants don’t react with water the same way R12 and R134A do forming an acid. If you do pull a vacuum they say don’t go more then 10 inches. I’m going to anyway just to see if my system will hold plus I feel that any moisture in the system is still not a good thing.
That kit includes everything you need to fill your system. Even the cheapest kit for $25 would be fine if you know how much you need to put in. A manifold gauge set would be handy for more troubleshooting.
In reply to PseudoSport:
If there's moisture in the system, the TXV will get corroded and stop working and the compressor will fail. It has little to do with the reaction with the refrigerant. If in fact that is what they say, it's just another example of why people should stop screwing around with these alternative (and unapproved) refrigerants and just use the correct refrigerant.
In reply to Sky_Render:
Why don't you just determine what you have in the system now? If R-12, then top it off with R-12. If R-134A, then do a conversion. Don't screw around with these half baked substitutes. They ALL have shortcomings.
I did a bastard 134 conversion on my 78 Delta 88. No vacuuming, no parts, no oil change. It worked about 4 years until the car went to the junk yard. Cooling wasn't the best and compressor growled some, but it was better than nothing and all I could afford at the time.
That said, I've done a proper job of repairing AC systems too. That one worked as good as new. If you can afford it, do it right.
I've also used R290 (propane) to charge a system. My shop heat pump has been running it for 3 months now, replacing the R22, and it will freeze you out. It also draws less amperage. So not only does it cool well, it's more efficient. It's used a fair amount in other countries.
The Envirosafe R12a is probably a mix of 60% propane and 40% isobutane with a scenting agent. That mix gives it characteristics similar to R12. The R22a is probably straight propane with the same scenting agent. It's a drop in replacement for R22. The scenting agent they use is a pine scent. The mercaptan used in regular propane can turn to sulfuric acid when exposed to moisture.
If you do use the R12a or even the R22a, do the future AC techs a favor and mark it as such. That way he's not smoking a cigarette when the system dumps pressure in his face or he tries to solder a leak shut. 
You'll need to log in to post.
