Cooling System Pressure Test

Pressure test the electric drive unit cooling system to identify leaks in hoses, connections, radiator, or heat exchanger components on the 2023 Chevrolet Bolt EUV.

Warnings

Tools required

Parts

• DEX-COOL coolant (if topping off) × 1 — ACDelco 10-5027

Fluids

• ACDelco DEX-COOL (Orange) — 0.5 qt

Preparation

1. Ensure vehicle has been off and cooling system is completely cool to the touch (minimum 2 hours after last operation)
2. Place vehicle on level surface and engage parking brake
3. Open hood and secure with prop rod
4. Place drip pans under engine bay to catch any coolant spillage
5. Verify coolant reservoir level is at COLD FULL mark before testing
6. Visually inspect all visible coolant hoses and connections for obvious damage or leaks before pressure testing

Procedure

1. 1

   Access coolant reservoir and remove cap
   Locate the coolant reservoir on the driver's side of the engine bay. Slowly turn the pressure cap counterclockwise to the first stop to release any residual pressure. Wait for any hissing to stop, then continue turning to remove the cap completely. Inspect the cap gasket for damage or deterioration.
2. 2

   Install pressure tester adapter
   Select the correct adapter from your pressure tester kit that fits the coolant reservoir opening on the Bolt EUV. Thread or lock the adapter securely onto the reservoir neck, ensuring a proper seal. Verify the adapter is seated completely and will not leak during pressurization.
3. 3

   Attach pressure tester
   Connect the pressure tester to the installed adapter. Ensure the connection is secure and the tester gauge reads zero PSI before beginning. If the gauge shows pressure, release it and verify all connections are properly seated.
4. 4

   Pressurize the cooling system
   Slowly pump the pressure tester to bring the system up to the specified test pressure of 15 PSI (103 kPa), which matches the cooling system cap rating. Do not exceed 20 PSI. Monitor the gauge as you pump to avoid over-pressurization.
   ⚠Pump slowly and watch for sudden pressure drops which indicate a significant leak. Stop immediately if coolant begins spraying.
5. 5

   Observe initial pressure hold
   Once at 15 PSI, stop pumping and observe the gauge for 2 minutes. A properly sealed system should hold pressure with no more than 1-2 PSI drop. Document the initial pressure reading and any immediate pressure loss.
6. 6

   Inspect coolant reservoir and cap area
   While system is pressurized, carefully inspect the coolant reservoir itself for cracks, the cap adapter seal for leaks, and all connections to the reservoir. Look for coolant seepage, wet spots, or active drips. Use a flashlight to check underside of reservoir.
7. 7

   Inspect radiator and heat exchanger
   Examine the front-mounted radiator assembly for leaks at the core, side tanks, and inlet/outlet connections. Check the electric drive unit heat exchanger connections and hoses. Look for coolant droplets, wet spots, or discoloration indicating previous leaks.
8. 8

   Inspect all hoses and clamps
   Systematically check each coolant hose connection from the drive unit to the radiator, including heater hoses. Inspect hose clamps for tightness and proper positioning. Look for bulging hoses, soft spots, or weeping at connection points. Use a mirror to inspect hoses on the backside of components.
9. 9

   Check drive unit coolant connections
   Inspect the electric drive unit coolant inlet and outlet connections for leaks. Check the inverter cooling passages and any quick-disconnect fittings. These areas are common leak points and may require careful inspection from underneath or with a mirror.
10. 10

    Monitor pressure for extended test
    Continue observing the pressure gauge for a total test time of 10-15 minutes. The system should maintain at least 13 PSI during this period. A healthy system may drop 1-2 PSI due to temperature stabilization, but continued pressure loss indicates a leak requiring further investigation.
11. 11

    Release pressure and remove tester
    Once testing is complete, slowly release pressure using the tester's relief valve. Allow pressure to drop to zero before disconnecting the tester from the adapter. Remove the adapter from the coolant reservoir and set aside.
12. 12

    Check and adjust coolant level
    Verify coolant level in the reservoir is still at the COLD FULL mark. Add DEX-COOL coolant if needed to bring to proper level. Install the original pressure cap by aligning the tabs and turning clockwise until it stops, then turn an additional 1/4 turn until it clicks into the locked position.

Reassembly

1. Ensure coolant reservoir cap is properly installed and locked in place
2. Wipe up any spilled coolant from engine bay components and painted surfaces
3. Remove drip pans and dispose of any collected coolant properly
4. If leaks were found and repaired, repeat pressure test to verify repair success

Verification

• System should hold 15 PSI with no more than 2 PSI loss over 15 minutes
• No visible coolant leaks, drips, or wet spots anywhere in the cooling system
• Coolant level remains at COLD FULL mark after test
• If system failed to hold pressure, identify and repair leak source before returning vehicle to service
• Document test results including initial pressure, final pressure, time duration, and location of any leaks found

Related trouble codes on this vehicle

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