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How to Fix AC in Cars with a Low Refrigerant

How to Fix AC in Cars with a Low Refrigerant

How to Fix AC in Cars with a Low Refrigerant


A car without a working AC can be a nightmare, especially during those sweltering hot days in the summer. If your AC is not working, it can be due to different problems, and the most common ones include weak airflow or less cooling capability. If you are facing such issues and wondering how to fix AC in cars with a low refrigerant, we are here to give you some quick solutions.

However, you must also know how to diagnose the problem since the refrigerant might not be the problem. Also, you must also have an idea what are the right tools to use. That said, not all problems may be repairable on your own, in which case you will have to go to a professional.

How to Diagnose the AC Problem: The Basics

The initial step is to find out what exactly is wrong with your car’s AC. So, start your car and turn the AC on, setting it to the coolest temperature. Wait for a minute or two and check the airflow and note how cold it is. If it is cool but not as cool as it used to be, you could have the following issues:

  • Weak Airflow

There could be a few numbers of reasons behind this. First, see if the fans on your radiator are running. If they are not running, there is an electrical issue with the wiring of these fans.

Another prevalent cause of weak airflow is that the cabin air filter is old and clogged, and needs to be replaced. Thus, once you take your car for regular maintenance, always have the air filter checked to determine if it needs to be replaced.

  • Compressor Issue

If the AC is not capable of cooling the car, the compressor might be the underlying cause. The compressor is located in the engine bay. For this, check the pulley on the side of the engine and the center pulley. There is an electrical clutch that engages when the AC is turned on. This makes the center pulley turn on as well.

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If the center pulley is not rotating and the clutch does not engage, it could mean the compressor is broken or is out of refrigerant. A technician can guide you too if it needs to be replaced or just filled up with coolant. Also, the compressor clutch might not be engaging because of an electrical fault. This wire may need to be replaced if this is the problem.

  • Leaks

Leaks are a very common problem with AC systems in cars, especially when your car is old. The best way to go about this is to get a leak detection kit. These systems quickly let you know where the leak is happening. It basically consists of a dye that seeps through any leaks and makes it visible.

You need to connect it to the low side service spot. Then spray it into the system and observe the AC system in your hood. If there is a leak, you will need a technician’s help to fix it. If there is no leak, it means that the air is not cool because the refrigerant is low.

How to Fix AC in Cars: Refilling the Refrigerant

The common problem which is low refrigerant is something you can fix on your own. If your diagnosis has led you to the conclusion that perhaps your car AC needs a refrigerant refill, go ahead and buy a refrigerant recharge kit.

  • Step One

Get the right refrigerant for your car. Generally, you can look it up in your car’s manual. Nevertheless, the refrigerant in most modern cars is R134a.

  • Step Two

If you have a thermometer, check what is the ambient temperature because the refrigerant changes volume depending on the temperature. Meaning, it expands and contracts. Hence, in order to correctly gauge the refrigerant volume, the temperature should be noted.

  • Step Three

Next, you need to locate the low side service port of the AC system. There are two ports, the high side, and the low side. This is the nozzle located at the bottom. Just follow the line from the compressor, and you will locate it.

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Once located, clean the line and cap with a rag. Then, remove the cap and clean the port. You do not want any debris to go into the port; hence, be very careful with this. Your refrigerant refill kit comes with a hose that connects the can to the port.

Connect one end of it to the service side port, then, connect the other end to the nozzle of the gauge and then to the can. You can get this gauge separately too in case one did not come with your kit.

  • Step Four

Read the ambient temperature chart to determine the pressure on the gauge. Also, note the pressure the refrigerant is already at according to the ambient temperature chart. The kit and can have the instructions already, and it is good if you read those just to be sure.

Turn the valve until the seal of the can is punctured and the refrigerant is released. You need to rotate it clockwise, and as you do, the refrigerant would start flowing into the AC’s port. Make sure to keep the can upright all the time.

Shake the can occasionally to enforce pressure and force the refrigerant out. Once the gauge indicates that it is full, remove the hose and put the cap back on the port. If your car was not too low on refrigerant, chances are, the can may still have some coolant left. You can keep it for the next recharge.

  • Step Five

Finally, turn the car on as well as the AC to the fullest fan and cooling setting. Also, observe the compressor if it is running. If the compressor is running and the airflow is as cool as it should be, you are good.

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If you have detected any leaks or other problems in the process, have a technician look at it immediately. Leaks can be dangerous as they introduce moisture into your car’s AC system.

How to Fix AC in Car: The Conclusion

Refilling the refrigerant is quite simple, and you can do it at home, saving you money to take it to a service and have it done by a technician. Plus, your kit can be used for other cars as well if they ever need a refrigerant refill.