What’s in that air con system? The strange story of HFO-1234yf

What’s in that air con system? The strange story of HFO-1234yf

Following the long awaited phase out of R134a in automotive air conditioning systems, due to it’s high global warming potential (GWP), air con specialists AACTA bring you right up to date with the chaotic political saga that is the global roll out of replacement R1234… Sitting comfortably? Then we shall begin at the start of last year.


January 2012Subaru introduced the new XV and Hyundai released the i30 using using HFO-1234yf (R1234) in the AC system, closely followed by Mazda and Kia.

April 2012Shortage of R1234 led to the EU allowing car makers to fill new type vehicles with R134a until the end of 2012. Many vehicle manufacturer models, including Mercedes “B” & “S” class, were made with production line R134a.

 September 2012 – Following the European Automotive Air Conditioning Conference (EAAC) there was growing confidence that R1234 would finally be readily available to manufacturers and the aftermarket ready for the January 1st 2013 deadline.

 After 6 years of testing and development by the vehicle and the associated equipment manufacturers, all the main issues except maybe the cost of the new refrigerant looked as though had been finally resolved. Many new models of vehicles were now ready to leave the production line with R1234 refrigerant in their systems until…

 October 2012German press announced that Daimler, the manufacturer of Mercedes-Benz cars, stated it will not be using R1234 and wished to continue using R134a due to “safety concerns” from its own tests.

Concerns had been raised previously as to its “mild” flammability but the climate-friendly R1234 had been determined by laboratory and crash tests to be safe. Daimler claimed it’s own additional tests went beyond the legally prescribed requirements finding:

“In the new real-life test scenario, the refrigerant is dynamically dispersed at high pressure near to hot components of the test vehicle’s exhaust system. This corresponds to a serious head-on collision in which the refrigerant line is severed and the reproducible results demonstrate that refrigerant which is otherwise difficult to ignite under laboratory conditions can indeed prove to be flammable in a hot engine compartment.” 

October 2012 – SAE International, the standards-setting association representing automotive engineers, says it is working with an international group of car manufacturers to to investigate the safety of R1234. 

December 2012The European Commission has declared that the MAC directive will be fully implemented on January 1 despite the safety concerns expressed by Daimler over refrigerant R1234. The EC restated that from January 1 2013 refrigerant R134a will be banned in all new type-approved cars.

February 2013Confidence in the safety of R1234yf as an automotive A/C refrigerant continues to grow in the ranks of an SAE International. It determined that the refrigerant release testing completed by Daimler (and cited by the OEM as the basis for its decision to discontinue use of R1234yf) was unrealistic by creating the extremely idealized conditions for ignition while ignoring actual real-world collision scenarios.

Daimler who were originally involved have since withdrawn. Vehicle manufacturers now include Chrysler/Fiat, Ford, General Motors, Honda, Hyundai, Jaguar Land Rover, Mazda, PSA, Renault, and Toyota. BMW and Audi have also dropped out.

Reacting to Daimler’s withdrawal, refrigerant manufacturer Honeywell commented “It shows an unwillingness to accept SAE’s proven, scientific, peer-based approach that repeatedly demonstrated R1234 is safe. Daimler’s testing was conducted without the participation of any reputable third party and without consultation with others in the industry. Also, this testing came on the eve of the MAC Directive, despite the fact that automakers had six years to prepare for compliance.”

April 2013 –  The market is still confused as to which of the above vehicle manufacturers have launched vehicles filled with R1234yf and what vehicles will be filled with it in the near future.

 The list of possible vehicles with R1234 in either now or in the near future is as follows:

  • HYUNDAI i30
  • LEXUS GS450h
  • PEUGEOT 301


But until you actually lift the bonnet and locate the service ports or labels, even dealers cannot be 100% sure!


Please look out for more updates in due course.


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