RAM 2500 Truck 4WD V8-5.9L VIN Z LDC (1998)
Expansion Block/Orifice Tube: Testing and Inspection
The fixed orifice tube can be checked for proper operation using the following procedure. However the fixed orifice tube is only serviced as a part of the
liquid line unit. If the results of this test indicate that the fixed orifice tube is obstructed or missing, the entire liquid line unit must be replaced.
WARNING: THE LIQUID LINE BETWEEN THE CONDENSER OUTLET AND THE FIXED ORIFICE TUBE CAN BECOME HOT
ENOUGH TO BURN THE SKIN. USE EXTREME CAUTION WHEN PERFORMING THE FOLLOWING TEST.
1. Confirm that the refrigerant system is properly charged. See Refrigerant System Charge in the Service Procedures.
2. Start the engine. Turn on the air conditioning system and confirm that the compressor clutch is engaged.
3. Allow the air conditioning system to operate for five minutes.
4. Lightly and cautiously touch the liquid line near the condenser outlet at the front of the engine compartment. The liquid line should be hot to the
touch.
5. Touch the liquid line near the evaporator inlet at the rear of the engine compartment. The liquid line should be cold to the touch.
6. If there is a distinct temperature differential between the two ends of the liquid line, the orifice tube is in good condition. If there is little or no
detectable temperature differential between the two ends of the liquid line, the orifice tube is obstructed or missing and the liquid line must be
replaced.
