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Servicing automotive a/c systems: The difference between R-134a and R-1234yf

I get a lot of questions about automotive air conditioning products. It’s understandable, considering how rapidly refrigerant technology has changed over the years. It’s also a relief, because it’s crucial that these products are used correctly.

Modern automotive air conditioning systems can be extremely expensive to repair or replace. If you don’t follow the manufacturer’s recommended service, if you use improper equipment, or if you use the wrong refrigerant or lubricant, catastrophic damage can occur. Even worse? It could cause serious injury to the technician.

Here are some of the factors to consider when servicing auto a/c systems:

Air conditioning refrigerants

Due to environmental concerns, air conditioning refrigerants have continued to change. Older refrigerants, like CFC-12 (R-12), have been blamed for depleting the ozone layer. This prompted a switch to refrigerants like HFC-134a (R-134a), which aren’t considered ozone-depleting.

However, increasing concerns about climate change have moved the industry away from older refrigerants because of their higher global warming potential (GWP). R-12 isn’t just unfriendly to the ozone layer, it has a GWP value of 10,900! R-134a, while non-ozone depleting, is still viewed unfavorably due to its GWP of 1,430.

The new player in the market is HFO-1234yf (R-1234yf), which is considered ozone-friendly and has a GWP of less than 1. Problem solved, right? Not so fast.

Why you can’t use R-134a in an R-1234yf system

We now have an environmentally friendly refrigerant on the market, but it’s not commonly retrofitted to R-134a systems due to the enormous associated cost. R-1234yf is almost exclusively used for all new vehicles.

The contamination of air conditioning systems—by using the wrong refrigerants—can damage expensive components. In fact, this is such an issue that it’s often recommended to use hoses, adaptors, and equipment dedicated to each kind of refrigerant to avoid the risk of contamination. 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. Not only does this negate the environmental benefits of R-1234yf, but it’s also a violation of Federal Law under Section 203 of the Clean Air Act and is considered “tampering” with a vehicle’s emissions control device.

The contamination of air conditioning systems—by using the wrong refrigerants—can damage expensive components.

Modern evacuation equipment used in R-1234yf systems can detect impurities and won’t allow evacuation if the refrigerant isn’t considered pure.

Air conditioning lubricants

Changes in refrigerants also meant changes in compressor lubricants. Compressor oils have to be the right type and viscosity intended for use in each particular system.

BG Frigi-Charge® for R-134a, PN 704, contains R-134a (as the name implies) and is only intended for use in systems designed for this refrigerant. BG Frigi-Quiet® for R-134a, PN 701, is a suitable compressor oil for systems utilizing R-134a, but it’s not compatible with R-1234yf.

However, BG Frigi-Quiet® for R-1234yf, PN 702, is suitable for use in systems that use R-1234yf and R-134a because it was formulated with extremely high quality and purity oil in order to suit the performance requirements of both refrigerants.

This makes it a versatile compressor oil for many of today’s air conditioning systems. However, we don’t recommend the use of dye in this oil because it can degrade the oil’s quality, which is what allows it to be so universal.

Air conditioning lubricants for hybrid vehicle a/c systems

Hybrid electric vehicles (HEVs) use polyol ester oils (POE) for lubrication. These oils are not compatible with BG Frigi-Quiet® for R-134a, PN 701 or BG Frigi-Quiet® for R-1234yf, PN 702. BG doesn’t currently offer any air conditioning lubricants or refrigerants compatible with HEVs!

Using non-compatible products can potentially lead to catastrophic and extremely expensive damage to the air conditioning system. Furthermore, POE oils are dielectric, or insulating, which means they have a lower potential to conduct an electric current than other compressor oils do. Why is this significant? Because it protects the technician who’s performing the service.

These dielectric oils insulate the very high-energy components of HEVs. Even a small amount of non-POE oil or lubricant can reduce POE oil’s dielectric resistance. It doesn’t take much contamination to allow an electrical current to come into contact with the technician and cause injury.

Always adapting

Automotive air conditioning technology continues to change rapidly. Therefore, our products and services must adapt. The days of one size fits all in the automotive air conditioning world are over.

BG Products prides itself on being the leader in aftermarket automotive products and services. And part of our responsibility as industry leaders is to make sure we provide the right types of products and services and that the service technician stays safe

Andy Berlin

BG Product Technical Service Representative

Andy Berlin brings 24 years of experience as a chemist and product technology advisor to the BG Products R&D team. He acts as a technical advisor, helping international and domestic distributors and sales representatives understand BG product chemistry and applications. Andy writes technical articles for the BG Blendr’ and contributes content for use in social media and digital marketing.

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