Complete coolant system flush for the dual motor AWD electric drivetrain, replacing all EV Battery/Motor Coolant to maintain optimal thermal management of battery pack and electric motors.

Warnings

Tools required

Parts

• Lower coolant hose O-ring × 2 — Use OEM specification
• Drain plug seal washer × 2 — Use OEM specification
• Underbody panel clips × 5 — Use OEM specification

Fluids

• EV Battery/Motor Coolant — 10 qt

Preparation

1. Park vehicle on level surface and apply parking brake
2. Power down vehicle completely and remove key fob to at least 15 feet away
3. Access vehicle settings and enable Service Mode to lock out high voltage system
4. Allow coolant system to cool for minimum 2 hours if vehicle was recently operated
5. Raise vehicle safely using floor jack and support on jack stands at all four corners
6. Remove front undertray and rear underbody panels to access coolant drain points
7. Place coolant drain pan beneath vehicle centered under battery pack
8. Document current coolant level and condition before draining

Procedure

1. 1

   Connect diagnostic tool and prepare system
   Connect Rivian diagnostic tool to OBD-II port. Navigate to thermal management system menu and record current coolant temperatures for all three circuits (front motor, rear motor, battery pack). Verify all temperatures are below 40°C (104°F) before proceeding. Disable thermal management system through diagnostic tool to prevent pump activation during drain.
2. 2

   Drain front motor coolant circuit
   Locate front motor coolant drain plug on bottom of front drive unit, passenger side. Remove drain plug and seal washer, allowing coolant to drain completely into pan. Once drained, inspect drain plug threads and replace seal washer. Reinstall drain plug finger-tight only at this stage.
3. 3

   Drain rear motor coolant circuit
   Locate rear motor coolant drain plug on bottom of rear drive unit, driver side. Remove drain plug and seal washer, allowing coolant to drain into pan. Inspect drain plug threads for damage and replace seal washer. Reinstall drain plug finger-tight only.
4. 4

   Drain battery pack coolant circuit
   Locate battery pack coolant drain point at center-rear of battery enclosure. This is accessed through an access panel in the underbody. Remove drain plug and seal washer carefully as this circuit holds the largest volume. Allow minimum 15 minutes for complete drainage. Replace seal washer and reinstall plug finger-tight.
5. 5

   Disconnect lower coolant hoses for complete flush
   Disconnect lower coolant hose at front motor coolant reservoir to ensure old coolant is fully evacuated. Use panel tool to release hose clip and carefully separate hose from fitting. Inspect O-ring for damage and replace if any cuts, cracks or compression set is visible. Repeat for rear motor circuit lower hose connection.
6. 6

   Flush coolant circuits with fresh fluid
   Using coolant refill funnel, pour approximately 2 quarts of fresh EV Battery/Motor Coolant into front motor reservoir until it flows from disconnected lower hose connection. This flushes residual old coolant from circuit. Repeat process for rear motor circuit. For battery pack circuit, add 3 quarts through battery coolant fill point to flush system.
7. 7

   Reconnect hoses and tighten drain plugs
   Reconnect all lower coolant hoses with new O-rings, ensuring hose clips are fully seated and secure. Tighten all three drain plugs to secure. Since no torque specifications are provided in database, tighten drain plugs to snug specification following manufacturer service information accessed through diagnostic tool.
8. 8

   Refill front motor coolant circuit
   Locate front motor coolant reservoir fill cap and remove. Using refill funnel with adapter, slowly add fresh EV Battery/Motor Coolant until level reaches MAX line on reservoir. Add approximately 2.5-3.0 quarts. Do not overfill. Install fill cap hand-tight.
9. 9

   Refill rear motor coolant circuit
   Locate rear motor coolant reservoir fill cap and remove. Using refill funnel, slowly add fresh EV Battery/Motor Coolant until level reaches MAX line. Add approximately 2.5-3.0 quarts. Install fill cap hand-tight.
10. 10

    Refill battery pack coolant circuit
    Locate battery pack coolant expansion tank fill point (typically in rear cargo area under access panel). Add fresh EV Battery/Motor Coolant until level reaches MAX line. This circuit requires approximately 4.0-5.0 quarts. Total system capacity is 10 quarts across all three circuits.
11. 11

    Bleed coolant system using diagnostic tool
    Using diagnostic tool, access thermal management bleeding procedure. This will activate all three electric coolant pumps in specific sequence to purge air from system. Follow on-screen prompts, which typically cycles pumps for 10-15 minutes. Monitor coolant reservoir levels during bleeding and top off as needed as air is purged and fluid level drops.
12. 12

    Verify system and check for leaks
    With diagnostic tool still connected, command thermal management system to activate all cooling circuits simultaneously at medium flow rate. Inspect all hose connections, drain plugs, and reservoir caps for any coolant leaks. Check under vehicle with inspection light for any drips. Allow system to run for 5 minutes while monitoring for leaks.
13. 13

    Final level check and system test
    After bleeding cycle completes and pumps shut down, recheck coolant levels in all three reservoirs. Top off to MAX line as necessary. Total fluid added should equal approximately 10 quarts. Exit Service Mode through diagnostic tool. Using thermal management system menu, verify all three circuits show proper coolant temperature sensor readings and no fault codes present.

Reassembly

1. Reinstall all underbody panels and undertray with new clips as needed
2. Lower vehicle from jack stands and remove jack
3. Dispose of old coolant properly at recycling facility - do not mix with conventional coolant as EV coolant has different composition
4. Clear any temporary fault codes related to Service Mode through diagnostic tool

Verification

• Power up vehicle and verify no coolant-related warning messages appear on instrument cluster
• Using diagnostic tool, verify coolant temperatures for all three circuits (front motor, rear motor, battery pack) are reading normally and within 2-3°C of each other at ambient temperature
• Test drive vehicle for 15-20 minutes including moderate acceleration to activate thermal management system under load
• After test drive, recheck all coolant reservoir levels - should remain at MAX line with no significant drop indicating leaks or trapped air
• Perform final inspection under vehicle for any coolant leaks or drips around drain plugs and hose connections
• Verify using diagnostic tool that no thermal management fault codes are present and all temperature sensors are responding properly

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