Q: How to remove and install an expansion (orifice) tube in an air conditioning system for Chevrolet Avalanche,Silverado,Suburban,Tahoe,GMC Sierra,Yukon,Yukon Denali and Yukon XL?
A: To remove the A/C orifice tube from an air conditioning system, the system must first be discharged. The tube is located in the liquid (high-pressure) line near the accumulator and can be removed by holding the stationary fitting with one wrench and loosening the other fitting with another wrench. The tube has a fixed-diameter orifice and a mesh filter at each end, and can be removed with needle-nose pliers. If it is stuck or breaks off, a special tool may be required. The orifice tube meters the refrigerant, changing it from a high-pressure liquid to a low-pressure gas, and can be reused if the screens aren't plugged, torn, or the plastic housing is intact and the brass orifice is unrestricted. To install the A/C orifice tube, insert it with the shorter end pointing toward the evaporator, reconnect the refrigerant line, and have the system evacuated, recharged, and leak-tested.