GM Service Manual Online
For 1990-2009 cars only

Draining Procedure

    Warning: To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if radiator cap or surge tank cap is removed while the engine and radiator are still hot.

  1. Remove the surge tank cap.
  2. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
  3. Place a drain pan under the right side of the radiator.
  4. Open the radiator drain cock.
  5. Drain the cooling system.
  6. Inspect the appearance of the engine coolant for discoloration:
  7. • Discolored--Follow the flush procedure. Refer to Coolant System Flushing.
    • Normal in appearance--Follow the filling procedure.

Filling Procedure

    Caution: The procedure below must be followed. Improper coolant level could result in a low or high coolant level condition, causing engine damage.

  1. Close the radiator drain cock by hand.
  2. Lower the vehicle
  3. Note: Use a 50/50 mixture of DEX-COOL antifreeze and clean, drinkable water. It is necessary to maintain the coolant level near the cold fill line on the surge tank to ensure all the air has been purged from the cooling system.

  4. Slowly add a mixture of 50/50 DEX-COOL antifreeze and deionized water to the cooling system until the coolant level reaches the lower vent hose (1) on the surge tank.
  5. Note: Vehicles with air conditioning, switch air conditioning off.

  6. Install the surge tank cap.
  7. Start the engine and allow to warm up.
  8. Allow the engine to warm up at idling speed of up to 2,500 RPM until the first radiator fan setting switches on.

  9. Vent the cooling system.
  10. To vent the cooling system completely, allow the engine to run for 1 minute at 2,000 RPM to 2,500 RPM.

    6.1. Engine speed greater than 1,500 RPM.
    6.2. Engine at operating temperature.
    6.3. Gearbox in Neutral.
  11. Turn the engine off and allow to cool.
  12. Inspect the coolant level and also fill the coolant to the "COLD" mark.