GM Service Manual Online
For 1990-2009 cars only

Draining Procedure

    Caution: In order to avoid personal injury, do not remove the cap or open the cooling system drains from a hot system. Allow the system to cool first.


    Object Number: 931332  Size: SH

    Important: A 7.6 liter (8 qt) coolant container will be needed.

  1. Place the coolant container under the radiator drain cock located at the bottom of the right radiator end tank.
  2. Using a flat-bladed tool, open the drain cock and drain the coolant. A small amount of coolant will drain from the system.

  3. Object Number: 931323  Size: SH
  4. Remove the surge tank cap from the surge tank and the coolant will drain from the system.

  5. Object Number: 964352  Size: SH
  6. For L61 vehicles, if the engine block needs to be drained, a drain bolt is located near the bottom of the water pump assembly.

Filling Procedure

    Notice: All entrapped air must be purged from the powertrain cooling system before the final coolant level can be determined. Proper coolant level is critical to avoid engine damage.

    Important: The vehicle must be level when filling the cooling system.

  1. Slowly add a mixture of 50/50 DEX-COOL antifreeze and clean water to the coolant surge tank. Fill the cooling system as indicated below:
  2. • For L61 vehicles when the engine block is not drained, add 3.5 liters (3.7 qts)
    • For L61 vehicles when the engine block is drained, add 6 liters (6.3 qts)
    • For L66 vehicles, add 5 liters (5.3 qts)
  3. Start the engine and check for leaks.
  4. Run the engine and cycle the vehicle from idle to 3,000 RPM in 30 second intervals until the engine cooling fan comes ON, the engine cooling fan turns ON at approximately 102°C (216°F). Repeat this process twice before the engine is turned OFF.
  5. Return the engine to idle, and idle for 30 seconds, then turn the engine OFF.
  6. Allow the vehicle to cool, before adding additional coolant.
  7. Important: The level in the surge tank will return into the cold fill range once the vehicle cools.

  8. Add additional coolant to the surge tank until the level is approximately 13 mm (0.5 in) above the surge tank seam.
  9. Install the coolant surge tank cap.