How to Replace Auto AC O-Rings

by Baptist Johnson
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The air conditioning system on your vehicle is made up of several components. These components work together to create cold air, which blows through your AC vents. The condenser helps to remove heat from the system. It also traps refrigerant gas and converts it to liquid, which is a necessary step in the refrigeration process. Located near the pressure valves of the condenser are O-rings, which help prevent leakage. Once these rings are worn, they should be replaced immediately to prevent a refrigerant leak.

Step 1

Park your vehicle in a safe location. Open the hood of the vehicle. Locate the compressor in the hood area near the rear firewall. Identify the compressor as a silver cylinder with a fan mounted to the front side.

Step 2

Locate the AC service valves. The high-pressure valve is located on the AC hose that runs from the compressor to the accumulator. The low-pressure valve is located on the AC hose that runs from the compressor to the accumulator. Attach the hoses from the manifold gauges to the service valves. Attach the blue hose to the low-pressure valve. Attach the red hose to the high-pressure valve. Attach the yellow hose to a vacuum pump. Engage the vacuum pump. Evacuate your air conditioning system until the pressure gauge on the manifold gauges display 0 psi. Turn off the vacuum pump.

Step 3

Locate the condenser. Inspect the condenser. Notice that the condenser is connected to two hoses. The hose near the bottom of the condenser is the low-pressure AC hose. The hose near the top of the condenser is the high-pressure AC hose.

Step 4

Remove the low-pressure AC hose from the condenser using an adjustable wrench or a set of needle-nose pliers. The low-pressure hose O-ring is located in the area where the AC hose connects to the condenser. Remove the O-ring from the AC hose. Replace the O-ring with a new O-ring. Attach the low-pressure hose firmly to the condenser using an adjustable wrench or a set of needle-nose pliers.

Step 5

Remove the high-pressure AC hose from the condenser using an adjustable wrench or set of needle-nose pliers. Replace the O-ring with a new O-ring. Attach the high-pressure hose firmly to the condenser using an adjustable wrench or a set of needle-nose pliers.

Step 6

Recharge the air conditioning system with refrigerant. Attach a refrigerant can to the yellow hose of the manifold gauges. Open the valve on the yellow hose. Recharge the air conditioning system to its recommended pressure. Close the valve on the low-pressure hose when the pressure gauge reads between 25 and 40 psi. Close the valve on the high-pressure hose when the pressure gauge reads between 225 and 250 psi.

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