There are differences between 134 and R134A, though apparently R134 A is generically called R134. ( see 3 links below )

Refrigerant - Wikipedia, the free encyclopedia


The R-# numbering system was developed by DuPont and systematically identifies the molecular structure of refrigerants made with a single halogenated hydrocarbon.

The meaning of the codes is as follows:

Adding 90 to the number gives three digits which stands for the number of carbon, hydrogen and fluorine atoms, respectively.[10]
Remaining bonds not accounted for are occupied by chlorine atoms.
A suffix of a lower-case letter a, b, or c indicates increasingly unsymmetrical isomers.

For example, R-134a has 2 carbon atoms, 2 hydrogen atoms, and 4 fluorine atoms, an empirical formula of tetrafluoroethane. The "a" suffix indicates that the isomer is unbalanced by one atom, giving 1,1,1,2-Tetrafluoroethane. R-134 (without the "a" suffix) would have a molecular structure of 1,1,2,2-Tetrafluoroethane—a compound not especially effective as a refrigerant.



1,1,1,2-Tetrafluoroethane - Wikipedia, the free encyclopedia

Recently, 1,1,1,2-tetrafluoroethane (HFC-134a) has been subject to use restrictions due to its contribution to climate change. In the EU, it will be banned as of 2011 in all new cars.[2] The Society of Automotive Engineers (SAE) has proposed 1,1,1,2-tetrafluoroethane (HFC-134a) to be best replaced by a new fluorochemical refrigerant HFO-1234yf (CF3CF=CH2) in automobile air-conditioning systems.[3] California may also prohibit the sale of canned 1,1,1,2-tetrafluoroethane to individuals to avoid non-professional recharge of air conditioners.[4]


R134 and 134 auto

This thread is slightly misleading in the beginning. The A does not stand for Auto, they are discussing the differences between R134A destined for cars and R134A destined for stationary applications.