A/C Troubles in Your Vehicle: How to Replace the Orifice Tube

If your car’s air conditioner (A/C) appears to be having problems and you have probably discovered that cars make really effective ovens when the A/C is frozen. After a little bit of research, you can determine if there is a blockage in the lines and you can then decide to fix it yourself. Replacing the orifice tube is an important part of this process and should be done any time that your car’s A/C is serviced. Inside of the tube is a wire mesh, meant to catch any debris in the system before it is passed into the evaporator. As a result, it is common for this piece of equipment to become clogged, eventually freezing up your air conditioner. Replacing it is something that you can do yourself and with a little help from step-by-step instructions; it won’t even take you all day.

Directions

1

Read the Repair Manual

Before you begin taking your car apart, familiarize yourself with the type of A/C unit in your car. This is vitally important because:
*a) Some cars do not have a system that uses an orifice tube to regulate the pressure of the refrigerant before it enters the evaporator. Instead, they use a thermal expansion valve and it is not possible to replace one part with the other and have a functioning air conditioner.
*b) You need to know where in your car the unit is and exactly what it looks like. Take your time and be sure you really understand which tubes are air conditioner related and which ones are not.

2

Find the Orifice Tube

After familiarizing yourself with your car’s A/C unit and determining that it is, in fact, an orifice tube you are looking for, it’s time to find it. Begin by opening the hood of your car and locating the radiator. The orifice tube is in the Y junction of the tube that connects the front evaporator to the condenser. Sometimes it’s in the liquid line, sometimes in the evaporator inlet and sometimes in the condenser outlet. Your study of the repair manual will have told you which is true for your car. The tube you are looking for will most likely be along the side of the radiator, down towards the mounting.

3

Disconnect the Orifice Tube from Tubing

Using either a coupling wrench or an open-ended wrench, loosen the coupling. Refer to your manual if you aren’t sure you have the right place as cars do tend to vary but typically you will find the coupling near the upper end of the junction box, away from the radiator.

4

Take the Seal Out of the Line

Inside the tubing you will find a rubber seal. You cannot get to the orifice tube unless you remove the seal first.
*a) Look at the end of the liquid line coupling and locate the rubber seal.
*b) Remove the seal with needle nose pliers or a screwdriver.

5

Remove Orifice Tube

Once the rubber seal is out of the way, you will be able to see the orifice tube inside of the line. Use care while you work the tube out of the outer line. You can use pliers and you may need to work it back and forth within the line to get it out. Keep in mind that it is possible to break the orifice tube, making it much more difficult to remove from the liquid line.

6

Replace With New Orifice Tube

You can now install the new orifice tube, being sure to place it in the same direction as the old one. The smaller end should be pointing away from the coupling. Installation is simple but tricky and may require the use of pliers to get the new part situated properly within the line.

7

Replace Rubber Seal

Do not forget to replace the rubber seal. Do not attempt to use the old one for this, either; you must replace the rubber seal with a brand-new one.
*a) Make sure it is positioned properly and press it firmly into place.
*b) Using the wrench again, replace the nut and tighten it down securely.

8

Charge the Air Conditioner

This step is only something you can do by yourself if you have the proper equipment and know what you are doing, either from instructions or experience. Without experience or the proper equipment, charging the A/C is dangerous and should not be attempted. Take your car to a shop and have them charge it for you, for a nominal fee.

These instructions will enable you to handle your A/C maintenance on your own. Their air-flow from your unit will be much clearer now, providing you with some relief and a sense of a job well done.