AC Receiver/Drier

This procedure covers the replacement of the AC receiver/drier on a 1994-2007 Dodge Ram 2500 with the 5.9L Cummins diesel engine, including refrigerant recovery, component removal, and system recharge.

Warnings

Tools required

Parts

• AC receiver/drier assembly × 1 — Mopar 55116858AA or equivalent
• AC line O-rings (various sizes) × 1 — Use OEM specification
• PAG oil for AC system × 1 — PAG 46 or PAG 100 depending on compressor type

Fluids

• R-134a refrigerant

Preparation

1. Park vehicle on level surface and set parking brake
2. Allow engine to cool completely if recently operated
3. Verify AC system refrigerant type with identifier (should be R-134a)
4. Record refrigerant charge amount during recovery for proper refill
5. Ensure AC recovery machine is properly calibrated and oil separator is clean

Procedure

1. 1

   Recover refrigerant from AC system
   Connect AC recovery machine to service ports on the low and high side of the system. Follow machine manufacturer's instructions to completely recover all refrigerant from the system. Record the amount of refrigerant and oil recovered. Allow system to equalize to atmospheric pressure and verify no residual pressure remains before proceeding.
   ⚠️Refrigerant under pressure can cause severe injury. Ensure complete recovery before disconnecting any lines.
2. 2

   Locate receiver/drier assembly
   Open the hood and locate the receiver/drier on the passenger side of the engine bay. On 4WD models with the 5.9L Cummins, it is typically mounted on the right side near the firewall, attached to a bracket near the AC condenser outlet line. Verify which lines connect to the drier (typically the line from the condenser and the line to the evaporator).
3. 3

   Disconnect AC lines from receiver/drier
   Using appropriate line wrenches, disconnect the AC line fittings from the receiver/drier. Support the lines to prevent stress on the fittings. Use a flare nut wrench to avoid rounding the fittings. Immediately cap or plug all open fittings and ports to prevent moisture and contamination from entering the system. Remove and discard the old O-rings from the line fittings.
   ⚠Small amount of residual refrigerant or oil may escape when lines are disconnected. Work in well-ventilated area.
4. 4

   Remove receiver/drier mounting hardware
   Remove the bolts securing the receiver/drier to its mounting bracket. These are typically two mounting bolts that secure the drier clamp or bracket. On some models, the bracket may need to be loosened or removed for access.
   Torque spec

   Receiver Drier Bolts10 Nm (7 lb-ft)
5. 5

   Remove receiver/drier assembly
   Carefully remove the receiver/drier from the mounting bracket. Note the orientation of the drier for proper installation of the replacement. Inspect the removed drier for signs of physical damage, corrosion, or oil residue that might indicate other system issues.
6. 6

   Measure and transfer oil if necessary
   Drain the old receiver/drier into a clean container and measure the amount of oil removed. Check service information for total system oil capacity. Add the appropriate amount of fresh PAG oil to the new receiver/drier (typically 1-2 oz unless system has been severely discharged). Use the PAG oil viscosity specified in factory service information for your specific vehicle (note: any original R-12 system uses mineral oil, not PAG).
   ℹ️Different compressor types require different PAG oil viscosities. Using incorrect oil can damage the compressor.
7. 7

   Prepare new receiver/drier
   Remove the new receiver/drier from its packaging immediately before installation to minimize moisture absorption. Remove protective caps from the inlet and outlet ports. If not pre-oiled, add the calculated amount of fresh PAG oil into one of the ports and rotate the drier to distribute it internally. Install new O-rings on both AC line fittings, lubricating them lightly with PAG oil or refrigerant oil.
8. 8

   Install new receiver/drier
   Position the new receiver/drier in the mounting bracket in the same orientation as the original. Ensure the inlet (from condenser) and outlet (to evaporator) connections are correctly positioned for the AC lines. Install the mounting bolts finger-tight initially.
   Torque spec

   Receiver Drier Bolts10 Nm (7 lb-ft)
9. 9

   Reconnect AC lines
   Remove caps from the AC lines and receiver/drier ports. Inspect the new O-rings on the line fittings to ensure they are properly seated. Thread the line fittings into the receiver/drier ports by hand first to avoid cross-threading. Once hand-tight, use line wrenches to tighten the fittings to specification. Ensure lines are properly routed without kinks or excessive tension.
   Torque spec

   AC Line Fittings20 Nm (15 lb-ft)
10. 10

    Evacuate AC system
    Connect AC evacuation equipment to the service ports. Pull a vacuum on the system for at least 30-45 minutes to remove all air and moisture. The system should hold vacuum without rising for at least 10 minutes after the pump is shut off. If vacuum does not hold, there is a leak that must be repaired before proceeding.
    ⚠Inadequate evacuation will leave moisture in the system, which will damage the new receiver/drier and potentially the compressor.
11. 11

    Recharge AC system
    With the system under vacuum, charge with the refrigerant specified on the underhood label (R-134a on most models; early R-12 systems require a documented retrofit before using R-134a) to the amount specified on the underhood AC specification label (verify the exact charge capacity on your specific vehicle's label). Charge through the low-side port with the engine running and AC on maximum. Monitor system pressures with gauges to ensure proper charge level. Do not overcharge the system.
    ⚠Overcharging the AC system can cause poor performance and compressor damage. Follow exact specifications on the vehicle label.
12. 12

    Leak test system
    With the system charged, use an electronic leak detector or UV dye to check all connections for leaks, paying particular attention to the new receiver/drier line connections. Also visually inspect for oil residue around fittings. If any leaks are found, recover refrigerant, repair leak, and repeat evacuation and recharge procedure.

Reassembly

1. Verify all AC line connections are tight and properly torqued
2. Ensure receiver/drier mounting bolts are secure
3. Verify no tools or parts were left in the engine bay
4. Check that all AC lines have proper clearance from hot engine components and moving parts

Verification

• Start engine and turn AC to maximum cold with blower on high
• Allow system to run for 5-10 minutes and verify cold air output from vents
• Monitor AC pressures: low side should be 25-45 psi, high side should be 150-250 psi at ambient temperature (varies with temperature)
• Check that compressor cycles properly and clutch engages
• Verify no unusual noises from the AC system
• Inspect all connections for signs of refrigerant or oil leaks
• Confirm vent temperature is at least 20-30°F below ambient temperature
• Test AC performance in recirculation mode for maximum cooling

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