Which cars use R744 refrigerant in their air conditioning?

Searches for R744, R744 refrigerant and R744 gas are becoming more common as vehicle air conditioning systems change.

If your car needs an air con recharge or repair, it is important to know which refrigerant it uses before any work begins.

What is R744 refrigerant?

R744 is the technical name for carbon dioxide when it is used as a refrigerant. In vehicle air conditioning, it performs the same basic job as other refrigerants: it moves heat from the cabin so the vents can blow cold air.

The reason it matters is that R744 systems are built differently. They operate at much higher pressures than systems using older R134a or newer R1234yf refrigerants. That means the service ports, components, procedures and equipment must be suitable for R744.

R744 is often chosen because it has strong environmental credentials compared with many synthetic refrigerants. It is also useful in some modern climate control and heat pump systems, particularly where manufacturers want efficient heating and cooling from one integrated setup.

Which cars are most likely to use R744?

There is no single list that applies to every car, because the refrigerant can vary by model year, specification, market and whether a heat pump is fitted. However, R744 is most commonly found on selected modern premium vehicles, electric vehicles and hybrid vehicles with advanced climate systems.

Examples can include selected models from Mercedes-Benz, Audi, Volkswagen and Porsche, especially higher-specification cars or electric models with heat pump climate control. Some versions of the Mercedes-Benz S-Class, E-Class and related models have used R744. Certain Audi e-tron, Volkswagen ID and Porsche Taycan configurations may also use it.

This does not mean every vehicle from those brands uses R744. Many cars still use R1234yf, and older vehicles may use R134a. Two cars that look almost identical can have different refrigerants depending on production details and equipment fitted.

For this reason, the safest answer to “which cars use R744 refrigerant?” is: some modern vehicles do, but it must be confirmed on the actual vehicle before recharging or repair. If you already know your car uses CO2 refrigerant, BonAir has a dedicated R744 recharging and repair service page with more detail.

How to identify the refrigerant in your car

The first place to check is the air conditioning information label. This is usually found under the bonnet, near the front panel, on the slam panel, or close to the air con service area. The label should state the refrigerant type, such as R744, R1234yf or R134a, along with the correct charge amount.

A technician will also check the service connectors, vehicle data and system layout. R744 equipment is not interchangeable with standard air con machines, so the identification step is not just a formality.

If the label is missing, damaged or unclear, the system should not be topped up by guesswork. A proper check can avoid contamination, poor cooling and unnecessary component issues. This is especially important when a vehicle has been repaired previously or has had front-end bodywork, as labels and parts may have been replaced.

Why correct identification matters before recharging

R744 air con systems are designed for high-pressure operation. Using the wrong refrigerant, the wrong service machine or incorrect connectors can lead to unreliable cooling and may put components at risk. The compressor, valves, heat exchangers and seals all need to work within the pressures and specifications intended by the manufacturer.

Correct identification also protects service equipment. Mixing refrigerants can contaminate a recovery machine and create problems for future servicing. A trained technician will confirm the gas type before connecting equipment, recover any remaining refrigerant correctly and recharge to the specified amount.

R744 systems may also need different diagnostic thinking. Because pressures and temperatures behave differently from R1234yf or R134a systems, fault finding should be carried out using suitable gauges, data and procedures rather than assumptions based on a conventional air con setup.

What if the air con is not cooling properly?

Weak cooling is not always caused by low refrigerant. The issue could be a leak, pressure sensor fault, compressor control problem, condenser airflow issue, expansion device fault or electrical control issue. On vehicles with heat pumps, the climate system may also include additional valves and control strategies.

A recharge may be part of the solution, but the system should be assessed first. A professional check can confirm the refrigerant type, look for signs of leakage and test how the system performs once serviced.

If the air smells musty rather than simply failing to cool, the problem may be bacterial build-up in the ventilation system rather than the refrigerant circuit. In that case, an air conditioning antibacterial treatment can help freshen the cabin and reduce unpleasant odours from the vents.

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