1984 3090 Sd Freon
 

What is the advantage in converting to the new refrigerant>

Typo
 

That was supposed to say 300 SD

It's cheap to refill, but not worth the savings. Plus you live in Houston? Good luck!

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

300 SD Freon
 

OK, explain to me, what does being in Houston have to do with it? What are the advantages / disadvantages to the new stuff?

None of the alternative refrigerants are as efficient as R12 in an AC system designed for R12. I don't mean just fittings, I mean evaporator and expansion valve sizing, etc. I have R134a in the SDL. It's okay through 90F. Feels more like a swamp cooler than true AC above 100F; takes forever to cool and the blower never goes below max. I have R12 in the SE and the blower will turn down after a while. The S420 has a proper R134a system and 100F days aren't a problem. YMMV. Some folks say their R134a conversion is every bit as good as R12. I wouldn't chance it in a place at hot and humid as Houston.

Advantages - if your system has a simple to fix leak, you can fill with R134a for cheap or even do it yourself. If you're replacing the evaporator or compressor, the cost of R12 is small compared to the overall cost of the job unless you do it yourself.

Disadvantages - R134a is not as efficient a refiregerant as R12.

Ping Larry Bible. He can give you the full scoop. He might even have advice on how to make R134 work as well as R12.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

LOL

sixto - you have been around long enough to know what Larry is going to tell him:).

Jacob - do a search on this site. You will regret going to 134 in Houston on one of these cars:(. I live in a similar climate and I have converted two BACK to r12 and have been very happy with the reverse conversion. One of them is on a black 300D. I have seen the inside temp indicator be at around 125dF in August and the r12 does a good job of getting it comfortable in a fairly timely manner.