How to Recharge Air Conditioning with Freon in a Nissan Altima

If all of the air conditioner components are working properly in your Altima, you may need to recharge the system with refrigerant if it is blowing warm air. This is possible if your Altima is R134 compatible. Most models made in 1995 or prior to that use R12 refrigerant, so you would need to retrofit the system before you try to recharge it.
Difficulty: Moderate
Instructions
Things You'll Need
Goggles
Gloves
Leak detection kit
Pressure gauge
R134 refill kit
1

Test the air conditioning system for leaks. If your Altima is R134 compatible, you can use a leak detection kit from your local automotive store. Some of these kits will seal small leaks.
2

Find the Low Pressure Side service port. You will see a black cap on the line coming out of the compressor. Remove this cap. Look at the connector to determine if your car uses R134 or R12 refrigerant. You will notice screw type connectors on the both the High Pressure Side and Low Pressure Side lines in models using R12 refrigerant. They R134 compatible systems have a quick connect valve on the Low Pressure Side. Models made in or before 1995 may use the old R12 refrigerant. If this is the case, you must have your Altima's air conditioning system retrofitted to use R134 refrigerant.
3

Check your air conditioning system pressure using an automotive air conditioning pressure gauge. Keep in mind that in order to get an accurate reading, the air conditioner has to be turned on the coldest setting with maximum blowing power.
4

Attach the refill hose to the connector on the Low Pressure Side of the air conditioning system. Make sure that it is securely attached.
5

Allow the air conditioner to suck the refrigerant out of the can by slowly turning the valve on the refill kit hose. Pay attention to the way you hold the can. Most kits will have you hold the can upright when you recharge the air conditioning system. It may take as long as 10 minutes to empty a single can.
6

Close the valve on the refill hose and remove the hose from the connector when you have finished recharging the air conditioning system. Make sure that you put the cap back on the port.
7

Leave your Altima running for at least 20 minutes after recapping the port. This evenly distributes the refrigerant around the air conditioning system.

Tips & Warnings

In some areas you need a license to purchase all types of refrigerant including R134.

If the pressure is still low after you add one can of R134 refrigerant, you may need to add another. If this is the case, repeat Steps 3 through 7. Make sure to check the pressure often to ensure that the pressure stays below the dangerous level.

Always protect your eyes and skin by wearing safety goggles and gloves when working with the air conditioning system.

Because your air conditioning system is pressurized, you must be careful not to overfill it with refrigerant. Additionally, you should never try to add refrigerant to the High Pressure Side, which is marked with a red cap or a cap with an H or HIGH printed on it.

Never try to mix R134 and R12 refrigerant. This causes damage to the air conditioning system and may cause bodily injury. It is possible to retrofit a car that uses R12 refrigerant to accept R134.

Keep in mind that if the air conditioner is leaking, you must fix the leaks before recharging the system. It is illegal to discharge any refrigerant into the air. This includes recharging an air conditioning system you know is leaking refrigerant.