Recharge BMW A/C Air Conditioner
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Does your BMW Air Conditioner blow hot air? Learn how to fix it by following the procedures below. Recharging the BMW AC system with refrigerant will not restore your A/C if there is a leak in the A/C system.
Symptoms
Symptoms you may notice when your car’s air conditioner is low on refrigerant.
- Hot air blowing from air vents
- The A/C clutch doesn’t engage.
Before you start
- Always follow the instructions that come with the A/C Recharge Kit.
- A/C pressure will be high when the engine is turned off. This is normal.
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 between roughly the 2014 and 2021 model years.
- 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
- AC Recharge Kit
- Glasses
- Gloves
Procedure
- Start the engine and let it idle.
2. Ensure the vehicle is in Park.
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3. With the engine running, turn on the air conditioner system on your car. Set the temperature to MIN and the blower fan speed to MAX. Make sure the A/C button is pressed or is switched ON.
4. Open Hood. Pull the hood release under the dashboard twice. Secure the hood in the up position. Ensure the hood does not fall on you while refrigerating your BMW.
5. Locate the low-pressure air conditioner charging port. Remove the cap from the A/C charging port.
6. Connect the a/c recharge kit to the low-pressure line. With the engine running, take a reading and ensure the refrigerant pressure is low.
7. Connect the A/C recharge kit, and start the car. With the A/C recharge kit connected, read the gauge. Continue to the next if the A/C pressure reading is low.
8. With the engine running, recharge the A/C system until the reading falls within 45 and 55 psi. Always follow the instructions on the back of the A/C recharge kit carefully.
9. Once you reach the recommended pressure level, stop adding refrigerant to your BMW 5-Series AC.
Overcharging a BMW 5-Series A/C with refrigerant does not make the air blow colder air and can cause damage to the air conditioner system.
If your BMW blows hot air but no cold air, it may indicate that the A/C system is low on refrigerant. Even though other problems can cause a BMW to stop blowing cold air, low refrigerant is often the problem.
If your A/C works for a few days and then stops blowing cold air, it usually indicates a large refrigerant leak.
Frequently Asked Questions
BMW AC blows cold on one side.
The most common problem is the vent actuator in vehicles with dual-zone A/C. They can get stuck in one position and do not switch when you change the temperature. Vehicles that use duo-valves can also get stuck, in which case, half of the car blows hot air, and the other blows cold air.
AC blows cold when driving and hot when idling.
The cooling fan for the condenser may not be working.
The air conditioner blows cold air but not very hard.
The blower fan may be defective.
AC blows cold at idle but hot when driving.
AC may be low on freon. Also, check the low-pressure switch. If defective, it can prevent the compressor from operating.
Check these troubleshooting and repair guides for more help on your BMW.
