The mixing of R-134a with R-1234yf will change refrigerant pressure and may result in evaporator freeze-up on pressure control systems, reducing system airflow.
The two different gasses should not be mixed. You cannot fit the 1234yf connectors on a 134A system anyway as they are different sizes.
Still, the answer is an emphatic, “No.” Not only would a retrofit of this type negate the environmental benefits of R-1234yf, but it would also be a violation of Federal Law under Section 203 of the Clean Air Act: “tampering” with a vehicle's emissions control device.
HFO-1234yf (R-1234yf ) has a global warming impact value of 1 versus 1300 for R-134a. It breaks down chemically in the atmosphere in only 11 days versus 13 years for R-134a! While R-1234yf oils are backwards compatible with R-134a systems, R-134a PAG oils are not compatible with R-1234yf systems.
R-134a and R-1234yf systems have unique fittings so they can only be used with the appropriate corresponding refrigerants and equipment. R-1234yf is very expensive. This has led to end-users trying to replace the refrigerant in vehicles originally containing R-1234yf with R-134a, in an attempt to save money.
R134a and R1234yf are similar, however, R1234yf was created as a more environmentally friendly replacement to R134a. The biggest difference between the two, is that R1234yf is mildly flammable and does require special handling.
Switching to R1234yf refrigerant is a step towards a greener future, but it comes with higher costs due to advanced equipment, stringent regulations, and specialized training.
There are three refrigerants that can be used to replace R-134a: R-1234yf, R-152a, and R-744.
In with the new
The new refrigerant type uses ND-oil 12, also a PAG 46 oil but with additives specifically for the R1234yf type refrigerant.
Unlike many HVAC-related questions, the answer to this is an unequivocal no. This is true even if a product is advertised as mixable or even if a technician tells you it's OK to mix! Different refrigerants use different oils to lubricate the system, and these oils don't mix.
The Intergovernmental Panel on Climate Change has since added R-134A to its list of greenhouse gases, declaring definitively that this refrigerant is a poor choice for the future of the planet and its inhabitants.
It is anticipated that by 2025 all vehicles will contain 1234YF. Don't fret, however, if your current vehicle requires 134a. Though 134a is not compatible with 1234YF and is expected to be phased out, it is still in production and will continue as long as there is a demand for repair of older vehicles.
R-12 and R-134a are known to be very efficient at cooling but are not as energy efficient as 1234YF. Therefore, cars with 1234YF systems can have better fuel efficiency and emit fewer greenhouse gases.
In short, the answer is, "No!" Automotive refrigerants are volatile compounds that can have a negative effect on the environment. Combining them can have adverse effects, and cause damage to your car's A/C system.
The ACX universal flushing unit is designed for refrigerants R134a and R1234yf. A proper flush of the air conditioning system is one of the most important tasks to be carried out during repairs and after the replacement of a compressor.
Refrigerant types are not to be mixed.
POE oil has greater insulating properties than PAG and can help to protect the insulation on the windings, preventing electrical leakage. Using the wrong oil in hybrid vehicles may allow current to short circuit back through the A/C compressor, creating a shock hazard.
Most vehicles have a label or sticker under the hood that indicate whether the refrigerant used is R-134a or R-1234yf.
The US EPA is to ban a host of high GWP refrigerants including R404A, R134a, R407C and R410A in certain new products from as early as January 1, 2021.
The above research indicates that R1234yf can be used as a drop-in replacement for R134a, meaning that automotive manufacturers do not need significant modifications. Currently, the main issue with R1234yf is its mild flammability.
R513A was developed as a replacement refrigerant for R134a. R513A is a modern, non-flammable refrigerant designed to replace R134a in a wide range of applications. It provides a sustainable solution for both new systems and retrofits.
The EPA declared R-134a “unacceptable” for new vehicles as of model year 2021 but has not taken any action against R-1234yf and does not classify it as an environmentally persistent per- and polyfluorinated substance (PFAS) chemical.
When was the 1234YF introduced? The new Freon that is being used in vehicles was first introduced in 2013. Only a few vehicles had 1234yf in them. There are still vehicles out there that use 134a Freon.