You’ve probably seen an orifice tube in car A/C before. They’re the metal tubes attached to your car’s air conditioning unit and blow cold air through your vehicle’s cabin. However, there’s more to these little tubes than meets the eye. Here is everything you need to know about them:
What Is An Orifice Tube?
An orifice tube is a small plastic tube with two openings. It connects to your vehicle’s evaporator and channels air into the system. As the air passes through it, it’s chilled by coolant flowing through an expansion valve before entering your car via vents in the dashboard and elsewhere. The orifice tube is located at the base of the evaporator core, which means it needs to be within range of incoming air so that air can pass through it into your car’s passenger cabin.
How Does An Orifice Tube Work?
The orifice tube regulates air flow into your car’s A/C system. It does this by controlling the amount of refrigerant reaching your vehicle’s evaporator coil, which regulates how much heat can be removed from inside the cabin. When you turn on your A/C, a portion of your vehicle’s refrigerant escapes through a series of valves and tubes that connect to this device. The orifice tube can then control how much refrigerant enters the evaporator by opening or closing up until it reaches an equilibrium between outside temperature and cabin temperature.
How Does It Get Damaged?
Orifice tube damage isn’t usually an immediate concern—it only becomes one if you notice that your car isn’t cooling as well as it used to, especially when you drive through cool weather conditions where you’d normally expect good performance from your AC system.
In some cases, orifice tubes can be damaged by being hit by a rock or other debris. This is especially common in off-road vehicles used on rocky terrain and other harsh environments. Orifice tubes can also be damaged when the car is driven in direct sunlight for extended periods. The sun’s UV rays can erode the plastic over time and cause it to become brittle, resulting in cracks and leaks.
Symptoms Of A Defective AC Orifice Tube
You may have a defective AC orifice tube if you notice any of the following:
- Poor A/C performance. When you turn on your car’s A/C, the air conditioning compressor doesn’t start up or makes a loud noise while running; this might be a sign that the orifice tube is defective.
- The A/C compressor doesn’t turn on at all. This can happen if there is no refrigerant left in your system or too much refrigerant left in your system (which causes it to overheat).
- The A/C compressor doesn’t shut off after running for a certain amount of time—for example, 30 minutes or an hour—even though cool air continues to blow through the vents after that time has elapsed.
Service And Inspection
Once you understand how an orifice tube works, it’s important to know how to inspect and service your car’s A/C system for optimal performance.
To check the condition of the orifice tube, remove the air filter inside your vehicle’s A/C unit. Next, look at both sides of the cooling coil and determine if any discoloration on either side indicates that water has made its way into your system. If there is no discoloration or signs of moisture damage, your orifice tube should be fine, but if you do see signs of contamination, it may be time for a replacement.
If you’re replacing an orifice tube because it has become clogged with debris over time, then use caution when removing it as they are very fragile and can snap easily if handled incorrectly, so always wear protective gear such as gloves and goggles before working with this part to avoid injury during removal and installation processes respectively.