Where is orifice tube on 97 blazer?
Inside the smaller tube going into the evaporator core.
The plastic expansion tube contains a fixed diameter tube with a mesh filter screen at either end. It is located in the evaporator inlet pipe. It creates a restriction to the high-pressure liquid refrigerant in the liquid line, metering the flow of refrigerant to the evaporator as a low-pressure liquid. When the engine is turned OFF with the air conditioning operating, the refrigerant in the system will flow from the high-pressure side of the expansion tube (orifice) to the low-pressure side until the pressure is equalized. This may be detected as a faint sound of liquid flowing (hissing) for 30 to 60 seconds. This is a normal condition. When system diagnostics indicate a restricted expansion tube, it may not be necessary to replace it. Metal chips, flakes, or slivers found on the screen may be removed with compressed air. The expansion tube may be reused if: * The plastic frame is not broken. * The expansion tube is not damaged or plugged. * The screen material is not torn. * The screen is not plugged with fine gritty material.
