Visited dealer yesterday and while car was in Service (Steering Wheel Memory), I checked out a 2017 MKZ in the showroom. I saw that the refrigerant used is the new R1234yf. The Continental next to it uses R134a, like mine. The MKZ I test drove also had the R1234yf.
I've heard of R1234yf and know it is flammable. Chrysler had been using it for a couple years now.
I decided to google it. Found that a couple years ago, Mercedes refused to use it due to it being flammable, however the European Union is forcing Mercedes to use it in cars sold in the EU. Obviously, the US allows it.
Both my cars use R134a.
Back in 1995, all cars sold had to switch from the R12 that was being used to R134a. They said at that time that R134a would only be in use for twenty years. Well, twenty years is now. Many of us had to retrofit R134a to cars that had R12. Not a big problem to retrofit, but not so easy to change to R1234yf from R134a due to higher pressures and different compressors and evaporators.
I'm not saying R1234yf is good, bad, or anything. Just different and costly to service once car out of warranty.
Google it.
I've heard of R1234yf and know it is flammable. Chrysler had been using it for a couple years now.
I decided to google it. Found that a couple years ago, Mercedes refused to use it due to it being flammable, however the European Union is forcing Mercedes to use it in cars sold in the EU. Obviously, the US allows it.
Both my cars use R134a.
Back in 1995, all cars sold had to switch from the R12 that was being used to R134a. They said at that time that R134a would only be in use for twenty years. Well, twenty years is now. Many of us had to retrofit R134a to cars that had R12. Not a big problem to retrofit, but not so easy to change to R1234yf from R134a due to higher pressures and different compressors and evaporators.
I'm not saying R1234yf is good, bad, or anything. Just different and costly to service once car out of warranty.
Google it.

