AC refrigerant.

[hardtail_pride]

So i searched a bit and just had a question. My 90 loyale surprisingly has working ac, but could possible use a recharge. I know i need R12 and have to more or less be a professional to do this process. I found someone with an old can of R12 for 25 bucks, just wondering if its worth picking up and keeping for when my car needs the flush done? And Is it best to just take to a professional than try and do it myself? Thanks

[ivantruckman]

if your just topping the system off, you would need a charge hose and can tap for r12 as well, my r12 system uses half a 12 oz can a year, i would rather buy a can of r12 every year, rather than do a whole conversion to r134

if you convert it to another type of refrigerant you have to evacuate the whole system . i would not recharge the whole system with r12, but topping off would be fine

[zstalker]

I've heard that our shop has an R12 machine...I can check and get back to you on it. If so, you could do a proper evac and recharge.

...I'll check.

~Erik~

[presslab]

How big of an R-12 can for $25?

 

For the best performance sticking with R-12 will be the way to go. I wish I had R-12 in my car; I have the ES-12A hydrocarbon based refrigerant and it works pretty good, a bit better than R-134a.

 

I recently cleaned up my whole system. Drained all the oil from everything I could get to, flushed the system, new o-rings in most places, cleaned out the dryer (they are expensive, otherwise I'd have replaced it), new Ester oil, and ES-12A. It works well and the compressor doesn't make noise like it used to.

 

You should have seen the green goo I cleaned out of stuff. Yech.

[hardtail_pride]

Its the size you see for all the new versions at auto zone for just recharge. Nothing more than just a top off. Ya zstalker that would be sweet. I gotta stop by sometime. Its just busy with work and mountain biking and tinkerin with my subaru. One day i will though

[Scoobywagon]

OK, folks....here's the breakdown on refrigerants for mobile A/C use.

 

Up until 1994, cars came from the factory with R12. It is a ChloroFluoroCarbon (CFC), so the EPA has gone to a lot of trouble to get it off the market and, eventually, out of circulation entirely. So it has been taxed and evironmental-fee'd so that now you can only buy it if you have a license to use it and it costs about $80/lb. Also, when burned it becomes EXTREMELY toxic. If you should have a major leak develop under your hood while the engine is running, your engine will very happily spit out Phosgene Gas through your tail pipe. If you want to know what that will do to you (in the car) and the person following you, click here.

 

1994 was the first year that the EPA required new vehicles to be equipped with R134a. R134a (tetrafluroethane) is a HydroFluoroCarbon (HFC) and has been deemed by the almighty EPA a safer, cleaner alternative to R12. When burned, R134a produces Hydrogen Fluoride gas. R134a is less than half the cost of R12 at about $30/lb.

 

The other option is what is known as R12a. R12a is a hydrocarbon refrigerant. It is, in fact, a blend of hydrocarbons, specifically Butane and Propane. As such, various brands will perform differently because their formulations will likely be different. For this reason it is recommended that you do not mix brands of R12a as A/C system performance can be affected. Also, because it is a blend, in the event of a leak, the refrigerant is not recoverable because the lighter portions will leak off faster than the heavier portions. As for burning R12a, what you get out of the tailpipe will depend to some extent on what specific blend you have. But, as a rule, R12a is fairly hard to ignite. R12a will generally cost you about $25 per 6 oz can. That works out to about $66.67 per pound. That sounds like an awful lot, but that's really not the case when you get right down to it.

 

For comparison, we'll use R12 as the baseline for cooling capacity. We'll also assume that everything else in the system is equal. Really, we could just assume that we're repeatedly charging the same system with various refrigerants. If this theoretical A/C system requires 1 pound (16 oz, $80) of R12, it would require approximately 1.25 lbs (20 oz $37.50) of R134a or .625 lbs (10 oz, $41.66) of R12a. This reflects the difference in cooling capacity between the 3 refrigerants. So it sounds like you should go with R134a because its the cheapest, right? Maybe. But maybe not.

 

Since there's more R134a in the system to make it cool properly, you'll generally get higher head pressures at the pump. The compressor is having to work harder to move the refrigerant around properly and that leads to both reduced fuel mileage and, in some cases, reduced compressor life. Also, most cars require some form of conversion process in order to run R134a properly. That requires both parts and labor, the cost of which varies greatly from car to car.

 

Since there is LESS R12a in the system, you get a corresponding drop in head pressures leading to increased fuel mileage and improved compressor life. In this case, the EPA still mandates a "conversion" process. However, simply changing the service port fittings over from the R12 style fittings to the newer R134a fittings meets their criteria for a "conversion". And, because R12a is a direct replacement for R12, no further conversion is required.

 

As far as "flushing" out an A/C system...the reality is I've never seen that actually done at any shop, even those who advertise "A/C Flushing" service. There's simply no need. Most places that advertise A/C flushing service do nothing of the sort. All they really do is evac the system, replace the receiver/dryer and recharge. That's it. Most receiver/dryer's will run you $30-50. Cheap insurance when you think about it.

 

The green goo that you get out of the system is usually just oil with fluorescent dye in it. Most systems will have 4-7 ounces of oil in them. Larger systems will, of course, have more oil.

[presslab]

As far as "flushing" out an A/C system...the reality is I've never seen that actually done at any shop, even those who advertise "A/C Flushing" service. There's simply no need. Most places that advertise A/C flushing service do nothing of the sort. All they really do is evac the system, replace the receiver/dryer and recharge. That's it. Most receiver/dryer's will run you $30-50. Cheap insurance when you think about it.

 

 

Thanks for the info, that's a great summary.

 

Flushing is not real hard, I think the stuff I used was called HECAT. I just poured it into some stuff (not the dryer or compressor) and then blew it out with compressed air. Rinse, repeat.

 

The green goo that you get out of the system is usually just oil with fluorescent dye in it. Most systems will have 4-7 ounces of oil in them. Larger systems will, of course, have more oil.

 

Actually I'm pretty sure the green goo was not dye; it was a "bile green" color if you know what I mean. It was likely due to the previous attempt to convert to R-134a. The R-134a mixed with the R-12 type mineral oil causes corrosion of copper alloys.

 

The compressor also had a lot of brown dirty oil. I didn't flush the compressor (just rinsed it out with clean oil), but I'm sure the rest of the system was dirty too. I'd say for the relative ease a flush is definitely worth it if you want your AC to last a while.

 

www.autoacforum.com has a lot of good stuff.

 

 

P.S. The other night I had way too much Vodka, and I had the pleasure of seeing that bile green color. That's why I used that as a reference.

[presslab]

Its the size you see for all the new versions at auto zone for just recharge. Nothing more than just a top off. Ya zstalker that would be sweet. I gotta stop by sometime. Its just busy with work and mountain biking and tinkerin with my subaru. One day i will though

 

That sounds a little spendy for that much, but if you can recover your existing R-12 it might be just the ticket to refill it after you get your AC all up to snuff.

 

I have a lime green Chameleon with an internal gear hub and a 6" fork. Hardtails rule.

[edrach]

Regarding scoobywagon's comments: It's great to see someone talk about the facts and with some real understanding rather than the mis-information that I usually see posted when discussing A/C upgrades.

 

As to the original poster's comment on having found a can of R12: If I remember correctly, these are 16 ounce cans; judging from the label on my Brat's compressor, a full charge (not just topping up) of R12 requires 28 ounces of R12 refrigerant.

[GeneralDisorder]

I know at work we often "flush" refrigeration systems with nitrogen - it absorbs any moisture in the system.

 

GD

[jacobs]

The other option is what is known as R12a. R12a is a hydrocarbon refrigerant. It is, in fact, a blend of hydrocarbons, specifically Butane and Propane.

 

Propane works GREAT and can be mixed with R12 and oils used with R12. It is "illegal" to use in some states, however propane is very commonly used everywhere in the world except the US. Would DuPont have anything to do with that?

[presslab]

Propane works GREAT and can be mixed with R12 and oils used with R12. It is "illegal" to use in some states, however propane is very commonly used everywhere in the world except the US. Would DuPont have anything to do with that?

 

 

In my van I have 6.6 gallons of propane (for camping) about 8" away from the ground... So having 0.4 gallons of ES-12a (hydrocarbon, very similar to R-12a) in my air conditioning is no big whoop.

[hardtail_pride]

I heard propane is a very sketchy substance to use, because if it leaks into your interior and there is a spark BOOM! hehe

[TRAVIS75]

I work at a salvage yard, and we have recovery tanks for both r12 and r134. My ac hasn't worked since I did my motor swap (my fault, like a dumb@#$ it didn't occur to me to just unbolt the compressor and set it off to the side I let all the pressure out). Anyways, we hardly ever get r12 in, mostly because cars we get have been wrecked obviously, or the systems were empty and never refilled.

 

I've seen a product calle Freeze12 and its supposed to be universal for both r12 and 134. I've not tried it and haven't really looked for it. After reading the extensive and very fact filled post breaking down differences etc.. of the refrigerants, I have my doubts about how Freeze12 can truly be universal, something in the chemical comound make up of it surely doesn't jive from one to the other. But it is an option.

 

I opted to use our pump (seperate pump than the one used solely for recovery of the freon) to pump out my system. I then went to walmart and they sell a conversion kit, that comes with threaded conversion couplers to pump r134 into your system. They thread on to your existing lines but the nipple end is big enough to fit r134 hoses on. In the kit you get the hi/lo couplers for it, as well as a how to DVD (didn't watch) 3 cans of premixed (oil and 134) freon, as well as a piece you screw on to the top of can that has a a hose, trigger and pressure gauge so you can monitor how much pressure is in the system.

 

I know its not the 100% correct way, and I'll pay in some way down the line most likely, but its worked for 3 months for me, so who knows. The whole kit was 35 bucks.

[jacobs]

I heard propane is a very sketchy substance to use, because if it leaks into your interior and there is a spark BOOM! hehe

 

Yep...Very dangerous, just like 15-40 gallons of gasoline under your car or like propane in your home for heating. IF it was very dangerous, it wouldn't be allowed in your home or used in AC overseas.