Duracool is a refrigerant compatible with R12. Years ago, I bought a case of it. My brother in law was having some work done on his '81 Corvette and asked if he could have some of my Duracool since his R12 equipped Vette was low. When he took it to the shop, the mechanic noticed the "FLAMMABLE" warnings on the cans and said that he felt uncomfortable using it instead of R12.

Now, I've never heard of any issues at all in that regard. How about you guys?

 

I wouldn't worry about it. Hydrocarbon (HC) based refrigerants are only flammable in 2-9% concentrations of it and the air. I suppose if you sprung a leak in the evaporator and it leaked into the car at the same time you flicked a lighter, you could get a woosh of flame. But even then, you'd have to be in the 2-9% mixture ratio.

But the chances of the above are so slim, it's negligible. R-12 is flammable when combined with a 15% combination of mineral oil. Our cars came with that exact ratio of R-12 and mineral oil from the factory. How many R-12 fires have you heard of?

Most likely chance of a fire with any car refrigerant is going to be breaking the condenser in a front end accident. Especially when you have hot broken headlight filament there too. But even then, the HC are going to shoot forwards to the front of the car (ahead of the radiator). HC refrigerants use about 40% as much refrigerant as R-12/R-134a cars, so we're talking 1 lb of refrigerant at the most.

The mere act of a condenser crack shooting the refrigerant out is a good thing. Because if it didn't, then you would have the ingredients for a big boom or fire. Gasoline on the other hand will pool on the ground and give off flammable fumes for quite some time after a bad car accident. We carry 100 lbs of gasoline, but only 1 lb of HC refrigerant.

Put it to you this way, do you worry about driving home with a bottle of hair spray in your backseat? How about a can of computer dust off spray? (The dust off has R-134a in it)

HC refrigerants are used in Australia, Canada, and much of Europe with no worries. It's cheap, efficient, and works well with either R-12 or R-134a based system. It doesn't absorb moisture/corrosion like R-134a does either. All are reasons why shops don't like to use it. There's very little money to be made in a refrigerant that cools well and preserves the system's parts.

 

Thanks!