This procedure covers the removal and replacement of the EV chiller unit, which is part of the battery and drive unit thermal management system on the 2025 Rivian EDV 500.

Warnings

Tools required

Parts

• EV Chiller Unit × 1 — Use OEM specification
• Chiller mounting gasket/seal × 1 — Use OEM specification
• Refrigerant line O-rings × 4 — Use OEM specification
• Coolant hose clamps × 4 — Use OEM specification
• R-1234yf refrigerant × 1 — As needed for system capacity

Fluids

• EV Battery/Motor Coolant — 10 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow thermal management system to cool for minimum 2 hours if vehicle has been operated
3. Verify 12V battery is fully charged (chiller requires electrical diagnostics)
4. Disable high-voltage system using service disconnect located in rear underbody compartment
5. Wait mandatory 5 minutes after HV disconnect for capacitor discharge
6. Verify HV system is deactivated using digital multimeter at service points
7. Apply proper lockout/tagout procedure to HV disconnect
8. Raise vehicle on lift to access underbody components
9. Remove underbody aerodynamic panels to access chiller unit location in front underbody area
10. Place coolant drain pan under chiller unit location

Procedure

1. 1

   Recover refrigerant from system
   Connect refrigerant recovery machine to low and high-side service ports located near the chiller unit. Follow recovery machine manufacturer procedures to fully evacuate R-1234yf refrigerant from the system. Record amount recovered for comparison during recharge. Verify system pressure drops to zero on all gauges before proceeding.
2. 2

   Disconnect electrical connectors
   Locate the chiller unit electrical harness connector on the driver's side of the unit. Press the locking tab and disconnect the main power connector. Disconnect the temperature sensor connector on the coolant inlet side. Label connectors if necessary for reassembly reference.
3. 3

   Drain coolant from chiller circuit
   Locate the coolant drain valve on the bottom of the chiller unit or open the lowest coolant connection point. Allow EV battery/motor coolant to drain completely into drain pan. Expect approximately 3-5 quarts to drain from the chiller circuit. Keep drained coolant clean for potential reuse if not contaminated.
4. 4

   Disconnect refrigerant lines
   Using refrigerant line disconnect tools, separate the high-pressure and low-pressure refrigerant lines from the chiller unit. Cap all open refrigerant ports immediately to prevent moisture and contamination entry. Inspect O-rings and note their condition for replacement during reassembly.
5. 5

   Disconnect coolant hoses
   Using appropriate pliers or hose clamp tool, release the clamps on the coolant inlet and outlet hoses at the chiller unit. Remove hoses from chiller fittings. Additional coolant will drain at this point. Cap or plug hoses to prevent contamination. Inspect hoses for damage or deterioration.
6. 6

   Remove chiller mounting hardware
   Locate the four mounting bolts securing the chiller unit to the underbody frame rail or mounting bracket. Support the chiller unit weight while removing mounting bolts. Remove all mounting hardware and keep organized for reinstallation. Note: chiller unit weighs approximately 25-30 lbs.
7. 7

   Remove chiller unit from vehicle
   Carefully lower the chiller unit from the mounting location, maneuvering around any surrounding components. Guide refrigerant line brackets and electrical harness routing clear of the unit. Place removed chiller on clean work surface. Inspect mounting area for damage, corrosion, or coolant leaks.
8. 8

   Prepare new chiller unit
   Unpack new chiller unit and verify part number matches replacement specification for 2025 Rivian EDV 500. Install new mounting gasket or seal on chiller unit mounting surface. Install new O-rings on all refrigerant line connections, lubricating with appropriate refrigerant oil. Verify all ports are free of debris and protective caps are removed only during installation.
9. 9

   Install new chiller unit
   Lift new chiller unit into position, aligning mounting bolt holes with underbody mounting points. Route electrical harness and ensure no pinch points exist. Install mounting bolts hand-tight initially to allow for alignment adjustment. Once aligned, tighten mounting bolts in cross-pattern. Note: No specific torque values available in database - follow service manual specifications.
10. 10

    Reconnect coolant hoses
    Connect coolant inlet and outlet hoses to new chiller unit fittings, ensuring proper orientation. Install new coolant hose clamps and position clamps away from hose ends. Tighten clamps securely but avoid overtightening which may damage hoses. Verify hoses are fully seated on fittings.
11. 11

    Reconnect refrigerant lines
    Remove caps from refrigerant ports immediately before connection. Connect high-pressure and low-pressure refrigerant lines to chiller unit, ensuring proper line routing matches original configuration. Listen and feel for positive click engagement of quick-connect fittings. Verify connections are secure by attempting to pull lines away from unit.
12. 12

    Reconnect electrical connectors
    Connect the temperature sensor connector to the chiller unit inlet side until it clicks into place. Connect the main power connector to the chiller unit, ensuring locking tab engages fully. Verify no pins are bent or damaged. Check that harness routing matches original configuration with no tension or rubbing points.
13. 13

    Refill and bleed coolant system
    Fill the thermal management system with fresh EV Battery/Motor Coolant through the designated fill point. Use approximately 10 quarts total system capacity, adjusting based on amount recovered. Follow Rivian bleeding procedure to purge air from system, typically involving cycling the thermal management pump through diagnostic mode. Verify coolant level stabilizes at proper mark.
14. 14

    Evacuate and recharge refrigerant system
    Connect vacuum pump to refrigerant service ports and evacuate system to minimum 500 microns for at least 30 minutes. Monitor for vacuum decay to verify system integrity. Once evacuated, recharge system with R-1234yf refrigerant to specification (compare to amount recovered in step 1). Use refrigerant scale for accurate charging. Verify proper charge by monitoring system pressures.
15. 15

    Reinstall underbody panels and restore vehicle
    Reinstall all underbody aerodynamic panels removed during preparation, ensuring proper alignment and all fasteners are secured. Remove lockout/tagout from HV disconnect. Restore high-voltage system by reconnecting service disconnect. Lower vehicle from lift. Clear any diagnostic trouble codes that may have been set during service.

Reassembly

1. Ensure all refrigerant line connections are secure and properly seated with new O-rings installed
2. Verify coolant hoses are clamped securely with no leaks visible
3. Confirm all electrical connectors are fully engaged with locking tabs secured
4. Double-check that no tools or parts were left in underbody area before lowering vehicle
5. Ensure underbody panels are properly aligned and all fasteners are installed

Verification

• Activate thermal management system through vehicle interface and verify chiller unit pump activates without unusual noise
• Monitor coolant temperature sensors through diagnostic interface to confirm proper circulation and cooling
• Check all coolant connections for leaks while system is operating at temperature
• Use refrigerant leak detector to verify no leaks at refrigerant line connections
• Verify refrigerant system pressures are within specification (typically 30-50 psi low side, 150-250 psi high side at ambient temperature)
• Monitor for any diagnostic trouble codes related to thermal management system
• Test drive vehicle and verify thermal management system maintains proper battery and motor temperatures under load
• Perform final visual inspection of installation area for any coolant drips or refrigerant oil residue

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