VALVE-A/C EXPANSION
DESCRIPTION
The rear A/C expansion valve is of a thermostatic expansion valve (TXV) design and controls the amount of refrigerant entering the rear A/C evaporator. The rear A/C expansion valve consists of an aluminum H-valve type body (1) with an integral thermal sensor (2) and is located on the bottom of the rear HVAC housing, which extends through the rear floor panel behind the right rear wheel housing.
OPERATION
The rear A/C expansion valve controls the high-pressure, low temperature liquid refrigerant from the rear liquid line and converts it into a low-pressure, low-temperature mixture of liquid and gas before it enters the rear A/C evaporator. A mechanical sensor in the rear A/C expansion valve monitors the temperature and pressure of the refrigerant leaving the rear A/C evaporator through the rear suction line, and adjusts the orifice size at the rear liquid line port to let the proper amount of refrigerant into the rear A/C evaporator to meet the vehicle A/C cooling requirements. Controlling the refrigerant flow through the rear A/C evaporator ensures that none of the refrigerant leaving the rear A/C evaporator is still in a liquid state, which could damage the A/C compressor.
NOTE: Replacement of the refrigerant line O-ring seals and gaskets is required anytime a refrigerant line is opened. Failure to replace the rubber O-ring seals and metal gaskets could result in a refrigerant system leak.
The rear A/C expansion valve is factory calibrated and cannot be adjusted or repaired and must be replaced if found inoperative or damaged.
REMOVAL
WARNING: Refer to the applicable warnings and cautions for this system before performing the following operation (refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - FRONT - WARNING) and (refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - FRONT - CAUTION). Failure to follow the warnings and cautions could result in possible personal injury or death.
NOTE: Illustration shown with rear body cradle removed for clarity.
1. Disconnect and isolate the negative battery cable.
2. Recover the refrigerant from the refrigerant system (refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - FRONT - STANDARD PROCEDURE - REFRIGERANT SYSTEM RECOVERY).
3. Drain the engine cooling system (refer to 7 - COOLING - STANDARD PROCEDURE - COOLING SYSTEM DRAIN).
4. Raise and support the vehicle.
5. Remove the nut (1) that secures the underbody refrigerant lines (2) to the rear A/C expansion valve (3) which extends through the rear floor panel (4) behind the right rear wheel housing.
6. Disconnect the rear heater hoses (6) from the rear heater core tubes (5) which extend through the rear floor panel.
7. Disconnect the rear underbody refrigerant lines from the rear A/C expansion valve and remove and discard the O-ring seals and position the underbody line assembly out of the way.
NOTE: Illustration shown with heater hoses and foam seal removed for clarity.
8. Remove the two bolts (1) that secure the rear A/C expansion valve (2) to the rear evaporator tube tapping block (3).
9. Remove the rear A/C expansion valve from the rear evaporator tube tapping block and remove and discard the O-ring seals.
10. Install plugs in, or tape over the opened underbody refrigerant line and rear evaporator tube fittings and all rear expansion valve ports.
INSTALLATION
CAUTION: Be certain to adjust the refrigerant oil level when servicing the A/C refrigerant system (refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - FRONT/REFRIGERANT OIL - STANDARD PROCEDURE - REFRIGERANT OIL LEVEL). Failure to properly adjust the refrigerant oil level will prevent the A/C system from operating as designed and can cause serious A/C compressor damage.
NOTE: When replacing multiple A/C system components, refer to the Refrigerant Oil Capacities chart to determine how much oil should be added to the refrigerant system (refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - FRONT/REFRIGERANT OIL - STANDARD PROCEDURE - REFRIGERANT OIL LEVEL).
NOTE: Replacement of the refrigerant line O-ring seals and gaskets is required anytime a refrigerant line is opened. Failure to replace the rubber O-ring seals and metal gaskets could result in a refrigerant system leak.
NOTE: Illustration shown with heater hoses and foam seal removed for clarity.
1. Remove the tape or plugs from the opened underbody refrigerant line and rear evaporator tube fittings and all rear expansion valve ports.
2. Lubricate new rubber O-ring seals with clean refrigerant oil and install them onto the rear evaporator tube fittings. Use only the specified O-rings as they are made of a special material for the R-134a system. Use only refrigerant oil of the type recommended for the A/C compressor in the vehicle.
3. Install the rear A/C expansion valve (2) onto the rear evaporator tube tapping block (3) which extends through the rear floor panel behind the right rear wheel housing and install the two bolts (1). Tighten the bolts to 11 N·m (97 in. lbs.).
NOTE: Illustration shown with rear body cradle removed for clarity.
4. Lubricate new rubber O-ring seals with clean refrigerant oil and install them onto the rear underbody refrigerant line fittings. Use only the specified O-rings as they are made of a special material for the R-134a refrigerant system. Use only refrigerant oil of the type recommended for the A/C compressor in the vehicle.
5. Connect the underbody refrigerant lines (2) to the rear A/C expansion valve (3) and install the nut (1). Tighten the nut to 23 N·m (17 ft. lbs.).
6. Connect the rear heater hoses (6) to the rear heater core tubes (5) which extend through the rear floor panel (4) behind the right rear wheel housing and install the heater hose clamps securely.
7. Lower the vehicle.
8. Reconnect the negative battery cable.
9. Fill the engine cooling system (refer to 7 - COOLING - STANDARD PROCEDURE - COOLING SYSTEM FILL).
10. Evacuate the refrigerant system (refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - FRONT - STANDARD PROCEDURE - REFRIGERANT SYSTEM EVACUATE).
11. Adjust the refrigerant oil level (refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - FRONT/REFRIGERANT OIL - STANDARD PROCEDURE - REFRIGERANT OIL LEVEL).
12. Charge the refrigerant system (refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - FRONT - STANDARD PROCEDURE - REFRIGERANT SYSTEM CHARGE).