What refrigerant is in there?
 

I bought this car (1991 300D 2.5Turbo) a few months ago. It seems that the air conditioner could use a bit more refrigerant. It is still cooling but when it is really hot, it is not cutting it. The sign in the engine compartment says that is has R12. The service records that came with the car say that it was topped of by a Mercedes dealer a year ago with R134A Freon. Isn't R12 Freon and 134A a replacement? I'm a bit confused here. How can I tell what is actually in there?

Thanks .. Udo

R-12 was discontinued in 1995 because of its negative effects on the ozone layer. If your refrigerant was topped off a year ago, it is R-134A.

Maybe, but I had mine filled with R-12 last week. ;)

It is possible yours was "converted" to R-134a, but R-12 is still available.

Look at the A/C service ports. If they are the same size it's R12, if one is bigger than the other, its 134A.

i'm going to put some freeze 12 in my joint when i am ready.

http://autorefrigerants.com/co00030.htm

R 12 was discontinued in 1995, but not because of the effect on the environment. That was a good reason and it made a good claim for a product change, but R 12 was really discontinued because the DuPont family that had a patent on R 12 only had it for 100 years and it was about to expire. Reformulating R 12 into R134A gave the DuPonts another 100 years on a new formula and claiming to save the environment was good PR!;)

Patents don't last a hundred years, but you still might have something, Knight. Very conspiracy-theoretic, but still a lot of fun.

Too bad 134a is a very poor substitute for good old R12.

Forced, I hate to say it, but I've seen cars that were converted without the proper ports being added. I didn't do it, but it is certainly not out of the question. The only way to tell for sure is to have the refrigerant tested. The worst-case scenario is some of each.

Well it is true that your patent has to have merit, but if you can claim your original whatever has other uses different from the original intent, you can add an amendment to your patent every so often and extend it's life for 100 years! Like this: apply for one for your R12 formula used to keep ice in 1896. bring it to a boil in a percolator chamber like a percolator coffee pot and when it condenses into a liquid again it gets cold. All you need is an alcohol burner. Electricity was put into service in large areas like New York City in 1907 and hence the first electric motor driven compressor for a refrigerator and you have another amendment. Run the compressor faster with a smaller expansion valve in a tight chamber and you have the first deep freeze in 1916. Get another amendment. Come up with the first Air conditioner to cool radio broadcasting tubes at a high velocity air flow above freezing temps and get another amendment in 1928. Develop a commercial water cooled large capacity beverage cooler in 1936 and get an amendment. Develop a expanded version of the broadcasting tube cooler in 1939 and make it a whole house air conditioner and get another amendment. Making sense?Wine chiller barrels in 1942, flash freezers in 1949, automobile AC systems in 1953, portable AC in 1955, mass produced window AC units for consumer use in 1959, Reverse heat pumps in 1967, etc..... see? Now with anew formula you get to do it all over again because it is more friendly to the environment and it takes 10% less than R 12 for the same job so there is no comparison! Retrofitting older systems is another patent amendment, etc,etc,etc....:D

Knight,

I don't know about all these extensions, but I really don't have any reason to doubt it. Especially with what the USPTO allows even these days.

If I get a chance, I'll look up the history of R12 and its various patents. Of course, if you want to post a link or two here, I won't mind too much...

I'll look for a link or two, but my info came directly from a lawyer!:rolleyes: Figures huh?;)

It's too bad your in New York Udo, I have a refrigerant Identifier I could throw on for you.. It'll tell ya what's in there and what percentages.

How does this work?

I picked up a recovery tank full of a "mystery" refrigerant and would be interested in finding out what is it.

My mechanic has a "sniffer" that'll tell you exactly what's in there - you need an indy with the same tool.