Hyundai Air Conditioner A/C Recharge Instructions

If your Hyundai A/C  performance becomes poor and has been blowing hot air, the system may be low on refrigerant.

An A/C refrigerant leak can cause the system pressure to drop, making the compressor inoperative. This procedure will work if your HVAC system only has a minor A/C gas leak. 

How to Recharge A/C Refrigerant on a Hyundai

Before You Start: Which Refrigerant Does Your Car Use?

• Check the label under the hood. It lists the refrigerant type and the factory charge amount. Most cars built before about 2015 use R134a. Many newer cars use R1234yf; manufacturers switched model by model, mostly during the late 2010s and early 2020s.
• The two are not interchangeable. R1234yf systems use different service ports, so an R134a DIY kit will not connect, and mixing refrigerants contaminates the system and the recovery equipment shops use.
• A DIY can only top up a system that is slightly low. If the A/C stopped blowing cold completely, there is a leak. Find and fix it first, then have the system evacuated and charged by weight. See why the system must be evacuated before charging.
• Do not overcharge. Too much refrigerant raises system pressure, makes the vents blow warmer, and can damage the compressor. Stop when the kit gauge reaches the recommended range.
• Protect your eyes and hands. Liquid refrigerant can cause frostbite, so wear safety glasses and gloves.

What you will need

• R134a Refrigerant Recharge Kit
• Work Gloves
• Safety Glasses

Procedure

1. Park the Hyundai. Apply the parking brake, shift the gear lever to Park, and allow the engine to idle.
2. Turn the air conditioner ON. Set the climate control to the lowest temperature and the blower to the max.
3. Open the hood of your Hyundai. Locate the low-side pressure service port and remove the cap.

4. Locate the air conditioner charging port or service port. For Elantra models, the A/C port is behind the engine near the firewall.
5. If the coupler does not fit the service port, most probably you are attempting to connect your A/C recharge kit in the high-side pressure port, which is a different size than the low-side port. If you are still struggling to find the A/C charging port on your Hyundai, the video below shows where it is.

6. Next, connect the A/C charging kit.

7. Add refrigerant to your air conditioner system. Once you connect the gauge, have a look at it to read your air conditioner system’s pressure. If the pressure is low, the gauge reading will be in the white zone. If the pressure is normal, the gauge should be in the green or blue area, depending on the A/C kit you are using. You should not read in the HIGH / RED zone except when the car is turned off.

8. Keep the can UPRIGHT. As you charge the system, shake the can every two or three seconds while charging. Every few seconds, release the trigger to stop the charging process. Take a look at the pressure gauge. (It is normal for the gauge to show overcharging when the engine is turned off.) Don’t overcharge the A/C system. Stop recharging the A/C system once the pressure is within the acceptable range. Measurement should only be taken while the engine is running.

9. Disconnect the A/C recharge kit. Detach the quick connection from the A/C port. Reinstall the cap. Don’t overtighten the cap. Close the hood and enjoy your AC system.

Remember that a system with a large leak may lose the refrigerant quickly and require mechanic repair before being topped off with refrigerant.

This procedure is not recommended for empty A/C systems. On an empty A/C system, the air must be extracted with a vacuum pump. Topping off the Hyundai A/C system is very easy and can take up to twenty minutes, depending on the system’s capacity.

Frequently Asked Questions

Check which refrigerant your Hyundai uses first

This matters more than anything else on this page and it is easy to get wrong. Older Hyundai models use R-134a. Newer ones use R-1234yf, which Hyundai phased in across the range over model by model over the late 2010s and early 2020s. The two are not interchangeable. The label under the hood states which one your car takes, along with the exact charge weight in grams, and that label is the authority rather than the model year.

The service ports are deliberately different sizes so a R-134a can will not screw onto a R-1234yf system, and adapters that defeat that exist but should not be used. Putting the wrong refrigerant in contaminates the system, and any shop that later recovers it will find the contamination on their analyzer and charge you for disposing of a mixed charge. R-1234yf is also several times the price, which is why some people are tempted. It is not worth it.

Avoid cans containing stop leak or sealant

Many of the cheap recharge kits on the shelf include a sealant additive, and the packaging presents this as a feature. It is not. The sealant is designed to react with moisture and harden where refrigerant is escaping, and it cannot tell the difference between a leak and the inside of an expansion valve, a condenser passage or a recovery machine.

The practical consequence is that many shops will now refuse to work on a system that has had sealant through it, or will charge a substantial fee to flush it, because the stuff destroys the recovery and recycling equipment they are legally required to use. A can of plain refrigerant with no additives costs less and leaves your options open. If you want the system to hold its charge, the answer is to find the leak.

A system that needs recharging has a leak

Air conditioning is a sealed system. It does not consume refrigerant the way an engine consumes oil, so if the charge is low, it went somewhere. A small annual loss through the compressor shaft seal and the hose connections is normal on an older car, and topping up every couple of years is reasonable. Needing to top up every few months is not, and repeatedly refilling a leaking system means venting refrigerant into the atmosphere, which is both wasteful and, in the United States, a violation of federal clean air regulations.

Most leaks are found with an ultraviolet dye already present in the system or added with the refrigerant, then traced with a UV lamp after a few days of running. The usual places are the condenser at the front of the car, where stone damage and corrosion take their toll, the o-rings at hose junctions, the compressor shaft seal and the evaporator inside the dashboard. A dye trace costs very little and tells you whether you are looking at a ten dollar o-ring or an evaporator replacement.

When low refrigerant is not the problem at all

Before buying a can, rule out the things that produce identical symptoms. A blocked cabin air filter restricts airflow so badly that the air coming from the vents feels warm even with a perfectly charged system, and it is the single most common cause of poor cooling. A cooling fan that is not running will stop the condenser rejecting heat, so the air conditioning works at speed and fails in traffic. A failed blend door actuator mixes heater output into the airflow regardless of what the air conditioning is doing, and that one usually clicks or ticks behind the dashboard.

If the compressor clutch is not engaging at all and the charge is correct, the fault is electrical rather than mechanical. The system refuses to run the compressor when the pressure sensor reports a problem, and the reason is stored as a code in the climate control module. A full system scanner that reads the climate and body modules will show that code along with the live pressure reading the car itself is seeing, which is considerably more informative than the gauge on a recharge can.

More guides: browse all of our Hyundai repair and troubleshooting guides.

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