Replace or repair coolant lines in the EV battery and motor thermal management system, including draining and refilling the cooling system.

Warnings

Tools required

Parts

• EV coolant line assembly (as needed) × 1 — Use OEM specification
• Coolant line quick-connect fittings (if damaged) × 4 — Use OEM specification
• Hose clamps (if applicable) × 4 — Use OEM specification
• O-rings for coolant connections × 6 — Use OEM specification

Fluids

• EV Battery/Motor Coolant — 10 qt

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow cooling system to cool completely (minimum 2 hours after last operation)
3. Raise vehicle using appropriate lifting points and support securely on jack stands
4. Remove underbody shields to access coolant lines (specific panels depend on which lines are being replaced)
5. Connect diagnostic scan tool and verify high voltage system status
6. Using scan tool, disable high voltage system and confirm lockout status
7. Disconnect 12V auxiliary battery negative terminal and wait 5 minutes
8. Place coolant drain pan beneath work area
9. Photograph coolant line routing before disassembly for reference during reassembly

Procedure

1. 1

   Access coolant system service port
   Locate the coolant system service port on the cooling system reservoir. Remove the service port cap slowly to relieve any residual pressure. Listen for pressure release and wait until all pressure is relieved before fully removing cap.
2. 2

   Drain cooling system
   Using the diagnostic scan tool, activate the coolant drain procedure to open system valves. Locate the coolant drain valve on the battery thermal management system (typically on driver side of battery pack). Attach appropriate drain hose and open drain valve. Allow system to drain completely into collection pan. Expect approximately 10 quarts of coolant.
3. 3

   Disconnect electrical connectors
   Identify any coolant temperature sensors or flow sensors on the coolant lines being replaced. Carefully disconnect electrical connectors by releasing locking tabs. Secure connectors away from work area to prevent damage.
4. 4

   Release coolant line connections at battery pack
   Locate the quick-connect fittings where coolant lines attach to the battery thermal management system. Using hose clamp pliers or appropriate tool, compress the retaining tabs on each quick-connect fitting. Pull coolant line straight away from connection point. If lines are stuck, gently rotate while pulling. Inspect O-rings for damage and replace if necessary.
5. 5

   Release coolant line connections at motor/inverter
   Trace coolant lines to the motor and inverter cooling connections. Release quick-connect fittings at these locations using the same method as battery connections. Note that dual motor systems will have connections at both front and rear motor assemblies. Mark each line position if lines are similar to prevent incorrect routing.
6. 6

   Remove coolant line mounting brackets
   Identify all mounting brackets and clips securing coolant lines to vehicle chassis and components. Remove fasteners securing brackets and carefully release lines from all mounting points. Keep track of bracket locations and hardware for reinstallation.
7. 7

   Remove damaged coolant lines
   Carefully extract coolant lines from vehicle, noting routing path through chassis and around other components. Inspect routing path for any sharp edges or potential interference points that may have caused the original failure. Address any issues before installing new lines.
8. 8

   Prepare new coolant lines
   Unpack new coolant line assemblies and verify correct part numbers against service documentation. Inspect all quick-connect fittings and ensure O-rings are properly seated. Apply a small amount of EV coolant to O-rings to aid installation. Clean any debris from connection points on vehicle.
9. 9

   Install new coolant lines
   Route new coolant lines along the original path, ensuring proper clearance from all moving parts, sharp edges, and heat sources. Begin installation at the battery pack end and work toward motor/inverter connections. Ensure lines follow natural curves without kinking or excessive tension.
10. 10

    Connect coolant lines to components
    Push each quick-connect fitting straight onto its mating connection point until an audible click is heard. Verify proper engagement by pulling gently on each line - it should not separate. Install all connections at battery pack, front motor, rear motor, and inverter as applicable.
11. 11

    Reinstall mounting brackets and clips
    Secure all coolant line mounting brackets and clips according to documented locations. Ensure lines are properly supported but not over-tightened in brackets. Verify adequate clearance from suspension components, drive shafts, and steering components through full range of motion.
12. 12

    Reconnect sensors and close drain valve
    Reconnect all coolant temperature and flow sensor electrical connectors. Ensure locking tabs are fully engaged. Close the coolant drain valve and verify it is secure. Remove drain hose.
13. 13

    Refill cooling system
    Fill cooling system with new EV Battery/Motor Coolant through service port. Add coolant slowly to minimize air introduction. Fill to approximately 8 quarts initially. Using diagnostic scan tool, activate coolant fill assist function which will open valves and run pumps to distribute coolant through system. Monitor coolant level and add additional coolant as system accepts it until reaching proper level (total approximately 10 quarts).
14. 14

    Bleed cooling system
    Using diagnostic scan tool, initiate the coolant system bleed procedure. This will cycle coolant pumps and open bleed valves in a specific sequence to purge air from the system. Monitor coolant level during bleeding process and top off as needed. Continue bleeding procedure until no air bubbles are visible and coolant level stabilizes. Install service port cap.
15. 15

    Pressure test cooling system
    Connect coolant pressure tester to service port. Pressurize system to specification shown on diagnostic scan tool (typically 15-20 psi). Monitor pressure for 10 minutes. Pressure should not drop. Inspect all new connections for leaks. If leaks are found, release pressure, repair connection, and retest.

Reassembly

1. Reinstall all underbody shields and panels removed for access
2. Reconnect 12V auxiliary battery negative terminal
3. Using diagnostic scan tool, clear any cooling system fault codes
4. Enable high voltage system through scan tool
5. Lower vehicle from jack stands

Verification

• Using diagnostic scan tool, verify all cooling system sensors are reading normal values
• Check coolant level at service port - should be at proper cold fill level
• Start vehicle and allow cooling system to reach operating temperature while monitoring with scan tool
• Verify coolant pumps activate and temperature readings are within normal range for all zones (battery, front motor, rear motor, inverter)
• Perform visual inspection of all coolant line connections for leaks after system reaches operating temperature
• Check coolant level again after system has cooled - top off if necessary
• Test drive vehicle and monitor cooling system temperatures through multiple drive cycles
• Recheck all connections and coolant level after 24 hours of operation

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