Activities Hobbies Chevy Tahoe Expansion Block and Orifice Tube Locations The orifice tube is part of the air conditioning system Print Caiaimage/Trevor Adeline / Getty Images Hobbies Cars & Motorcycles Contests Couponing Freebies Frugal Living Fine Arts & Crafts Astrology Card Games & Gambling Playing Music Learn More By Matthew Wright Matthew Wright Matthew Wright has been a freelance writer and editor for over 10 years and an automotive repair professional for three decades specializing in European vintage vehicles. Learn about our Editorial Process Updated on 05/03/18 If your truck needed a new compressor because it seized up, there might be shrapnel scattered all through the A/C system. This would require a flushing of the system. The orifice tube is in one of the lines. Most likely it is in one near the accumulator. Look for a couple of little "dings" in the aluminum tubing. What Is an Orifice Tube and What Does It Do? The orifice tube is a restriction that lets the system have high pressure on one side of it and low pressure on the other. It also has a screen on it to act as a filter to catch any metal particles, but it doesn't catch them all. Sometimes they can be stuck in there and need a little heat to soften the O-ring that seals it to the inside of the line. Just make sure there is no metal in the lines or it will go through your new compressor and damage it. Locations of the Orifice Tubes for the 1996 Chevy Tahoe With Front A/C only, the Expansion Block/Orifice Tube is located in the condenser outlet pipe (high side line) at the liquid line connection. With Front and Rear A/C, the Expansion Block/Orifice Tube is located in a Y-shaped junction block in the tube between the condenser and the front evaporator. The junction block is located near the right side of the radiator support. The expansion tube is located between the junction block and the front evaporator. Finding the Orifice Tube for Other Vehicles For other makes and models of vehicles, refer to your owner's manual. If you still have difficulty in locating it, call the dealer's service center and ask for advice from a technician. You might also use their online question and answer sites to find this information. More on Your Vehicle's Air Conditioning System How Automotive Air Conditioning Works: Get familiar with the parts and operation of a vehicle's air conditioning system, including the compressor, condenser, evaporator, thermal expansion valve, drier or accumulator. How to Keep Your Truck's Air Conditioning in Top Shape: Learn the basic parts of your air conditioning system including the drive belt and condenser. Know the four signs that your air conditioner has a problem. How to Recharge Your Air Conditioner: Save money and recharge your air conditioner yourself with an AC recharge R134 kit. How to Test Your Air Conditioning System for Leak with a Dye Test: If you have recharged your system but it seems to need it every season, you may have a slow leak. Here's how to do a leak test.