A malfunctioning car air conditioner can be one of the most difficult problems to diagnose and repair. The first thing to look for are signs of leaks or a malfunctioning air conditioning compressor. If your air conditioning system requires substantial repairs, you may not have the equipment to do it at home. However, if you are low on refrigerant, you can recharge it using a recharging kit that you can buy at your local auto parts store.
Steps
Part 1 of 3: Identify the problem
Step 1. Start the vehicle and turn on the air conditioning
Use the key to start the car and turn on the air conditioning. Feel the air coming out of the air conditioner and assess how hot, cool or cold it is. If the air is warm to cold, but not as cold as it should be, there may be an airflow problem.
- Check to see if the radiator cooling fans are working. If not, there may be an electrical problem.
- You may need to replace the car's cabin air filter to increase airflow.
Step 2. Check if the air conditioning compressor works
You will need to make sure that the air conditioning compressor is working properly to determine the correct course of action to make repairs if necessary. Locate the air conditioner in the engine compartment and see if the center of the pulley rotates along with it.
- There is a clutch that is activated when the air conditioning works. With the clutch engaged, the center of the pulley will rotate along with it.
- If the clutch does not engage, the air conditioning compressor may be broken and require replacement, or you may simply need to fill it with refrigerant.
Step 3. Check the wiring leading to the air conditioning compressor
Most compressors have a cable that leads to the electric clutch. Find the connector in the middle of that cable and unplug it. Grab a piece of wire and run it from the compressor wire to the positive (+) battery terminal. If you hear a loud sound, you know that the electric clutch is working properly. Otherwise, you will have to replace it.
- You may have to use specialized tools to replace the compressor.
- Take the car to a repair shop in case the compressor or clutch needs to be replaced.
Step 4. Check the air conditioning system for leaks
You can purchase leak detection kits to help you identify any leaks present in the air conditioning system. These kits provide a dye that will pass through the lines and seep through any leaks or cracks, making them visible to the naked eye.
- Connect the leak detection kit to the low side service port and spray the dye into the air conditioning system.
- If you detect a leak, you should take the car to a repair shop.
- If you don't see any leaks, the problem may simply be that the coolant level is too low.
Part 2 of 3: Prepare to Add Coolant
Step 1. Buy the right type of coolant for your car
The easiest way to determine the correct type of coolant for your car is to check the year it was manufactured. All cars made after 1995 use R134a. If the car you have is older, then it probably uses R12.
- You cannot refill R12 refrigerant on your own.
- If the car uses R12, you should make an appointment with a car repair specialist to make the conversion.
Step 2. Check the room temperature with a thermometer
To read the refrigerant gauge, you need to know what the current ambient temperature is. The refrigerant takes up a different amount of space within the can and the air conditioning system at different temperatures, which causes the meter reading to be different at different times.
- Knowing the ambient temperature will allow you to have a more effective reading of the indicator found on the can of refrigerant.
- When the refrigerant expands to take up more space, the pressure in the can increases.
Step 3. Locate the low side service port for the air conditioner
The air conditioning system will have 2 service ports: a low side and a high side port. When you recharge the air conditioner, you will need to locate and identify the low-side service port.
- You can find the low side service port by following the air conditioning compressor lines until you find a nozzle near the bottom of the car.
- Consult your car's service manual to help you locate the port if you have problems.
Step 4. Use a rag to clean the area around the service port
Make sure not to clog it with dirt or debris when cleaning the port, cap, and surrounding area with the rag. First, clean the cap and line; then remove it and clean the port.
You can spray a brake cleaner on the line to help you clean it if necessary
Step 5. Connect the charging hose to the low side service port
Grab the hose that came with the coolant recharge kit and connect it to the low-side service port you identified earlier. Make sure the opposite end of the hose is connected to the nozzle of the can.
- If the can comes with a meter, the hose should be connected to the nozzle of the meter and then to the can.
- The hose should be long enough that you can connect it to the port without placing it completely in the engine compartment.
Step 6. Use a table of ambient air pressure on the gauge to determine the pressure
Read the meter's display while taking the ambient temperature into account to determine what level the coolant is currently at. Once you start spraying it, you will need to pay attention to the indicator to know when the system is full.
- Keep an eye on the gauge during system reload so you know when to stop.
- Read the instructions on the can if you are not sure how to read the meter.
Part 3 of 3: Refill the coolant
Step 1. Turn the valve until you puncture the seal on the can
Turn the valve on the top of the refrigerant clockwise until it breaks through the top and begins to release refrigerant through the hose and into the car's air conditioning system.
Some cans may require a different method to break the seal. Check the instructions on the can for guidance if needed
Step 2. Keep the can upright
As you allow the coolant to enter the car's engine, hold the can upright and shake it from time to time. If you turn the can to the side, the pressure will drop and it will not be able to refill the system.
- Shaking the can occasionally will help maintain pressure as you continue to force refrigerant into the system.
- Do not turn the can or hold it upside down.
Step 3. Pay attention to leaks
Watch for signs of leaks in the air conditioning system as you refill it. If you spot a leak, a professional mechanic will need to repair it. Make a note of where the leak is to make it easier to find and repair.
Leaks should be fairly easy to detect as you refill the system
Step 4. Remove the charging hose and store it in a cool place
Once the gauge indicates full, remove the hose from the service port and return the cap. If there is refrigerant left in the can, you can save it to recharge another car or to repair the same one another time.
- If the can is empty, you can dispose of it.
- Make sure the can doesn't leak if you put it away.
Step 5. Take the vehicle to a repair shop if necessary
If you detect a leak or if the air conditioning compressor is not working, you should take the car to a repair shop. Replacing an A / C compressor may require specialized tools, so it is generally beyond what most hobby mechanics can do.