Battery Cooling System Service

Service the battery thermal management system on the 2023 Chevrolet Bolt EUV, including coolant system inspection, coolant replacement, and cooling component verification.

Warnings

Tools required

Parts

• Battery coolant (DEX-COOL Orange) × 1 — ACDelco DEX-COOL
• Battery coolant inlet/outlet O-rings × 2 — Use OEM specification
• Coolant temperature sensor O-ring (if applicable) × 1 — Use OEM specification
• Battery pack cover seal/gasket (if damaged) × 1 — Use OEM specification

Fluids

• ACDelco DEX-COOL (Orange) — 10 qt

Preparation

1. Park vehicle on level surface and engage parking brake. Ensure vehicle has been off for minimum 2 hours to allow high-voltage system to cool.
2. Use scan tool to record any existing battery-related DTCs and document battery state of charge, temperature, and cell voltage readings.
3. Remove driver's seat lower trim panel to access high-voltage service disconnect located under driver's seat.
4. Remove high-voltage service disconnect by rotating counterclockwise and pulling straight out. Install lock/tagout device to prevent reconnection.
5. Wait minimum 5 minutes after disconnect removal for high-voltage capacitors to discharge.
6. Verify zero voltage across high-voltage terminals using properly rated high-voltage meter and safety gloves.
7. Disconnect 12V negative battery terminal and secure cable away from terminal.
8. Raise vehicle on lift and secure with safety locks. Remove front belly pan and underbody shields to access battery pack.
9. Place coolant drain pan under battery pack drain location.

Procedure

1. 1

   Access Battery Pack Cooling Connections
   Remove battery pack upper cover screws around perimeter of pack using proper sequence (start from center and work outward). Carefully lift cover to expose battery modules and cooling system manifold. Inspect cover gasket for damage and replace if torn or compressed beyond specification.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
2. 2

   Disconnect High-Voltage Battery Module Connectors
   Wearing high-voltage safety gloves, identify all battery module interconnect connectors (orange cables). Remove high-voltage connector bolts in reverse order of assembly (consult service manual for specific sequence). Carefully separate connectors and secure away from battery pack. Mark each connector location for proper reassembly.
   ⚠️Even with service disconnect removed, individual battery modules may retain charge. Handle all orange cables as energized.
   Torque spec

   Connector Bolts7 Nm (5 lb-ft)
3. 3

   Disconnect Battery Coolant Lines
   Locate battery coolant inlet and outlet lines at front of battery pack. Place drain pan directly under fittings. Slowly loosen coolant line fittings to relieve any residual pressure. Once pressure is relieved, fully remove fittings and drain coolant into pan. Remove and inspect O-rings; replace if hardened, cracked, or damaged.
   ⚠Initial coolant release may occur under pressure. Loosen fittings slowly and keep hands clear of spray path.
   Torque spec

   Coolant Line Fittings15 Nm (11 lb-ft)
4. 4

   Remove Cooling System Sensors
   Disconnect electrical connectors from coolant temperature sensors located on battery cooling manifold. Remove sensor bolts and carefully extract sensors from manifold. Inspect sensor O-rings and replace as needed. Check sensor resistance values with multimeter and compare to specification (typically 2.5k ohms at 20°C).
   Torque spec

   Sensor Bolts11 Nm (8 lb-ft)
5. 5

   Drain Battery Cooling System
   Locate battery cooling system drain plug at lowest point of battery pack cooling manifold. Remove drain plug and allow all coolant to drain into collection pan. If equipped with coolant reservoir specific to battery system, remove reservoir and drain separately. Inspect drained coolant for contamination, discoloration beyond normal orange color, or debris indicating system degradation.
6. 6

   Inspect Battery Cooling Passages
   With coolant drained, visually inspect cooling manifold passages and battery module cooling plates for corrosion, scaling, or blockage. Check all coolant passage connections for leaks or staining indicating previous leakage. If significant contamination is present, flush system with distilled water until clear, then blow out with compressed air at low pressure (max 20 psi).
7. 7

   Clean and Inspect Battery Terminals
   Remove battery terminal bolts from all affected modules during service. Using wire brush, clean all terminals and connection points of any oxidation or corrosion. Apply light coating of electrical contact grease to terminals. Inspect terminal bolts for damage or thread wear and replace if necessary.
   ⚠Corroded terminals increase resistance and can cause thermal management issues. Ensure all surfaces are clean and bright.
   Torque spec

   Battery Terminal Bolts7 Nm (5 lb-ft)
8. 8

   Reinstall Cooling System Sensors
   Install new O-rings on coolant temperature sensors lubricated with small amount of fresh DEX-COOL coolant. Insert sensors into manifold and install sensor bolts to specified torque. Reconnect electrical connectors ensuring positive lock engagement.
   Torque spec

   Sensor Bolts11 Nm (8 lb-ft)
9. 9

   Refill Battery Cooling System
   Close battery cooling system drain plug. Using coolant refill funnel at highest fill point, slowly add fresh ACDelco DEX-COOL orange coolant to battery cooling system. Fill to specification (approximately 10 quarts total system capacity). Pause periodically to allow air to escape. Gently massage coolant hoses to help release trapped air bubbles.
10. 10

    Reconnect Battery Coolant Lines
    Install new lubricated O-rings on coolant line fittings. Connect coolant inlet and outlet lines to battery pack, ensuring proper routing without kinks or sharp bends. Torque coolant line fittings to specification in gradual steps to ensure even O-ring compression.
    Torque spec

    Coolant Line Fittings15 Nm (11 lb-ft)
11. 11

    Reconnect High-Voltage Battery Connections
    Reconnect all battery module high-voltage connectors in proper sequence per service manual (typically reverse of removal). Ensure connectors are fully seated before installing bolts. Torque high-voltage connector bolts to specification following exact tightening sequence. Verify each connection is secure and properly aligned.
    ⚠️Improper torque or sequence on high-voltage connections can cause arcing, thermal events, or system damage. Follow service manual sequence exactly.
    Torque spec

    Connector Bolts7 Nm (5 lb-ft)

    Battery Terminal Bolts7 Nm (5 lb-ft)
12. 12

    Pressure Test Cooling System
    Connect cooling system pressure tester to battery coolant system. Pressurize system to 20 psi and hold for 5 minutes. Observe pressure gauge for any drop indicating leaks. Visually inspect all connections, sensors, and coolant lines for leakage. If pressure drop exceeds 2 psi, locate and repair leak before proceeding.
13. 13

    Reinstall Battery Pack Cover
    Inspect battery pack cover gasket and replace if damaged. Position cover on battery pack ensuring proper alignment with all mounting holes. Install cover screws following tightening sequence (center outward in cross pattern) to specified torque to ensure even gasket compression.
    Torque spec

    Cover Screws11 Nm (8 lb-ft)
14. 14

    Restore High-Voltage and 12V Systems
    Reconnect 12V negative battery terminal and torque ground cable bolt to specification. Remove lock/tagout device from high-voltage service disconnect. Reinstall service disconnect under driver's seat by inserting and rotating clockwise until fully seated. Reinstall driver's seat lower trim panel.
    Torque spec

    Ground Cable Bolt14 Nm (10 lb-ft)
15. 15

    System Initialization and Verification
    Reinstall underbody shields and belly pan. Lower vehicle. Using scan tool, clear any DTCs generated during service. Start vehicle and allow battery thermal management system to initialize (may take 2-3 minutes). Monitor battery coolant temperature and system pressure. Check scan tool data for proper coolant flow and temperature regulation. Allow system to run for 10 minutes while monitoring for leaks or abnormal operation.

Reassembly

1. Ensure all high-voltage connectors are torqued to exact specification and in proper sequence to prevent thermal issues
2. Verify battery pack cover is properly sealed to prevent moisture intrusion into high-voltage components
3. Double-check that service disconnect is fully seated and locked before returning vehicle to service
4. All underbody panels must be reinstalled to maintain proper battery pack aerodynamics and cooling

Verification

• Use scan tool to verify no high-voltage system DTCs are present and all battery modules show proper voltage balance within 0.1V
• Confirm battery coolant temperature sensor readings are within normal range (typically 15-25°C at rest)
• Verify coolant level remains stable after 24 hours of operation with no visible leaks under vehicle
• Test drive vehicle and monitor battery temperatures remain within normal operating range (20-35°C) under moderate load
• Perform final pressure test of cooling system after test drive to confirm all connections remain sealed
• Document final battery state of health, cell voltages, and coolant system parameters in vehicle service records

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