This topic is always similar to shouting "fire" in a crowded theater.
So many strong opinions, confusion, and speculation.

What enquiring minds would probably like to know is this:
Has anyone used a 100% Hydrocarbon (such as propane and/or butane) refrigerant in any vehicle, and did it work?

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1986 300E 5-Speed 240k mi.

There used to be an "alternative refrigerants" bulletin board over at aircondition.com. Alternative should be read as "roll your own out of grill gas." There were many positive testimonials, so yes, hydrocarbon refrigerants work just fine. I understand hydrocarbons are quite commonly used in refrigerators and/or home air conditioners in Europe. About the only complaint I recall is that hydrocarbons don't perform quite as well as CFC/HFC/etc. refrigerants in extremely hot temperatures - think Phoenix.

I've been playing around with R406a in my 124 wagon. (Autofrost is the brand name - http://www.autofrost.com ) It's a mixture of R-22, R-142b, and about 4% butane (forget the R-number for butane). It has the same pressure/temperature curve as R-12, but is capable of carrying more BTUs. In 18 months it hasn't destroyed the system, in fact it works fabulously. I drove the wagon down to the the hill country last weekend, and the a/c produced 30F duct temperatures with no problem. (I modified the ETR to permit the evaporator to get colder before cycling off the compressor.) Shoot, the thing was too darn cold, believe it or not.

Biggest problem for R406a is that it's a bit hard on o-rings. You need to hunt down and replace everything with neoprene. It can be a bit of a chore. Being a blend, it also tends to fractionate as it leaks, but this seems to be a bigger problem in theory than in practice.

In general I agree with the ever eloquent Larry Bible - stick with R-12. However, my personal stockpile of R-12 ran out two years ago. I don't care to find brittle o-rings and leaky evaporator joints using R-12 at $22/lb. Check the pricing at http://www.refrigerantsales.com - a cylinder of R-12 is $655, an equivalent cylinder of R-406a is $195. Wasn't a difficult choice for me to make.

- JimY

Interesting comments on the r406. Thanks.
Of course, since it contains r22, one would still need a 609 license to buy it, which is a barrier to entry.

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1986 300E 5-Speed 240k mi.

Thanks to LarryBible, I got mine at http://imaca.org in under an hour for $15. Can't beat a deal like that.

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Rick Miley
2014 Tesla Model S
2018 Tesla Model 3
2017 Nissan LEAF
Former MB: 99 E300, 86 190E 2.3, 87 300E, 80 240D, 82 204D Euro
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