AC Accumulator

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

Warnings

Tools required

Parts

• AC accumulator/drier × 1 — Mopar 4773287 or equivalent
• AC line O-ring kit × 1 — Use OEM specification
• PAG oil (compatible with R-134a) × 1 — Use OEM specification

Fluids

• R-134a refrigerant

Preparation

1. Park vehicle on level ground and set parking brake
2. Engine must be cold before beginning work
3. Ensure AC recovery machine is properly calibrated and has adequate tank capacity
4. Verify replacement accumulator is correct part number for 1994-2007 Ram 2500
5. Have new O-rings and PAG oil ready before opening system

Procedure

1. 1

   Recover refrigerant from AC system
   Connect AC recovery machine to high and low side service ports. Follow machine manufacturer instructions to completely recover all R-134a refrigerant from the system. Record the amount of refrigerant and oil removed for reference during recharge. Wait 5 minutes after recovery to ensure system is fully depressurized.
2. 2

   Locate and access accumulator
   The accumulator is mounted on the passenger side firewall near the evaporator. On 4WD models, you may need to remove the air intake duct for better access. The accumulator is a cylindrical canister with refrigerant lines connected at the top and a mounting bracket securing it to the firewall.
3. 3

   Disconnect liquid line from accumulator
   Using a crowfoot wrench and torque wrench, carefully loosen the inlet line fitting at the accumulator. This line comes from the evaporator outlet. Cap or plug the open line immediately to prevent moisture and debris entry. Remove and discard the old O-rings from the fitting.
4. 4

   Disconnect suction line from accumulator
   Loosen the suction line fitting at the accumulator outlet (line going to compressor). This is typically the larger diameter line. Cap or plug the open line immediately. Remove and discard the old O-rings from this fitting as well.
5. 5

   Remove accumulator mounting hardware
   Remove the mounting bracket bolt(s) securing the accumulator to the firewall. The accumulator may be held by a clamp-style bracket. Support the accumulator while removing the final fastener to prevent it from falling.
   Torque spec

   Mounting Bracket Bolts24 Nm (18 lb-ft)
6. 6

   Remove old accumulator
   Carefully remove the accumulator from the vehicle. Hold it upright and drain any remaining oil into a clean measuring container. Note the amount of oil removed - you will need to replace this plus any additional oil specified by the new accumulator.
7. 7

   Prepare new accumulator
   Remove caps from the new accumulator. Add the appropriate amount of fresh PAG oil through the inlet port (typically 2-3 oz, or match the amount drained plus 1 oz). Verify the new unit has the correct fittings and mounting provisions. Do not leave accumulator open for more than 15 minutes.
8. 8

   Install new accumulator
   Position the new accumulator in the mounting bracket on the firewall, ensuring proper orientation with inlet/outlet ports aligned to the refrigerant lines. Install the mounting bracket bolts and torque to specification.
   Torque spec

   Mounting Bracket Bolts24 Nm (18 lb-ft)
9. 9

   Install new O-rings on line fittings
   Lubricate new O-rings with a small amount of PAG oil and install them on both the liquid and suction line fittings. Ensure O-rings are properly seated in their grooves and not twisted or damaged.
10. 10

    Connect refrigerant lines to accumulator
    Hand-thread both refrigerant line fittings onto the accumulator ports to avoid cross-threading. Once hand-tight, use a crowfoot wrench and torque wrench to tighten both fittings to the specified torque. Do not over-tighten as this can damage the O-rings.
    Torque spec

    AC Line Fittings20 Nm (15 lb-ft)
11. 11

    Vacuum test the AC system
    Connect the vacuum pump to the AC system service ports. Evacuate the system to at least 29 inches of mercury (98 kPa) and hold for a minimum of 45 minutes. Monitor for vacuum loss - system should hold steady vacuum. If vacuum drops, there is a leak that must be found and repaired before proceeding.
12. 12

    Recharge AC system
    Using the AC manifold gauges and charging equipment, recharge the system with the correct amount of R-134a refrigerant as specified on the underhood A/C charge label for your specific vehicle. Add refrigerant through the low-side port with engine running and AC on maximum cold. Monitor pressures during charging.
13. 13

    Leak test all connections
    With system fully charged, use an electronic leak detector or UV dye to check all connections at the accumulator for leaks. Spray soapy water on fittings and look for bubbles. Pay special attention to the line fittings just installed. If any leaks are found, recover refrigerant, repair leak, and repeat vacuum and recharge process.

Reassembly

1. Reinstall any air intake ducts or components removed for access
2. Verify all tools and materials are removed from engine bay
3. Clean any spilled oil from firewall and surrounding areas

Verification

• Start engine and turn AC to maximum cold, maximum fan speed
• Verify cold air is blowing from all vents within 2-3 minutes
• Check that AC compressor clutch engages and cycles normally
• Monitor low side pressure (should be 25-35 PSI) and high side pressure (should be 200-250 PSI at 75°F ambient)
• Verify no abnormal noises from compressor or refrigerant lines
• Re-check all fittings for leaks after 24 hours of operation
• Confirm vent temperature is 40-50°F colder than ambient air temperature

Related trouble codes on this vehicle

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