Although even GM has come to the defense of Dupont in declaring the refrigerant R1234yf safe for use in passenger vehicles, Mercedes continues to stand by its contention that R1234yf can be flammable in certain real-world conditions. Late last year, Mercedes-Benz published the results of its tests, where a head-on collision ruptured the AC lines of the test vehicle, spewing the contents on the hot engine. This combination caused a fire which obviously left the German manufacturer uncomfortable and concerned.
With these results in mind, Mercedes applied and was granted dispensation by German federal authorities to continue using the tried and tested R134a refrigerant for a few more production vehicles. Specifically, these so-called modified vehicle approvals are for the A-Class (W176), B-Class (W246) and the SL (R231). Older production models were produced when the R134a standard was in force, so these are not a problem for Mercedes. It is these new production vehicles, specifically those from the beginning of the year that are mandated to use the new 1234yf refrigerant. Interestingly, Volkswagen AG has backed Mercedes’ contentions, although Opel, a GM subsidiary, has backed its parent company’s position.