Automotive AC Repairing and Replacing – Orifice Tube

The orifice tube is a metering device that is located inside the liquid line and can be found at some point between the condenser exit and the evaporator core inlet. It is recommended to remove the orifice tube any time that the system is recovered to inspect it for debris.

If the orifice tube is covered with debris, then the health of the system is not good and major repairs will need to be made. It is recommended that the orifice tube should be replaced any time it is removed. Here are the steps to follow when replacing the orifice tube.

Replacing the Orifice Tube

1. After recovering the AC system or verifying the system is empty, disconnect the lines at the orifice tube location. The connection may be a bolted connection or a quick-connect connection.

Orifice tubes can be located at the exit line of the condenser. This access point generally requires a little disassembly of the front section of the vehicle such as a headlight housing or front trim bezel. The O-rings or gaskets always need to be replaced whenever an AC system is open for any type of

2. Use small needle-nose pliers or a similar tool to carefully pull the orifice tube from the line.

The orifice tube can be removed from the mounting location by using small needle-nose pliers. The orifice tube generally can be removed without much resistance. However, if the tube does not come out easily, then some lubricant can be sprayed into the opening. Having the lubricant in place will assist in removing the old orifice

3. Inspect the orifice tube for debris and foreign materials.
4. Choose the correct replacement orifice tube and apply a couple drops of refrigerant oil at the O-rings on the orifice tube. Orifice tubes are available in several different sizes, which are
differentiated by color. Use the correct orifice tube for the given vehicle.
5. Install the new orifice tube into the line with the arrow on the device toward the evaporator core.

The new orifice tube is installed back into place by hand with the arrow on the orifice tube facing away from the condenser. The arrow faces in the direction of normal refrigerant flow. New O-rings need to be installed each time the system is being

6. Replace the O-ring on the line as well as apply a couple drops of refrigerant oil to the O-ring.
7. Reassemble the connection using the correct techniques. See the previous section on servicing the AC lines and hoses. See the previous section on servicing the AC lines and hoses.

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