GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2009 🢒 G8 🢒 Preface 🢒 Dangers, Warnings, and Cautions 🢒 Coolant System Flushing

Radiator Flush
  1. Drain the cooling system. Refer to Cooling System Draining and Filling.

    2. Warning: Refer to Safety Glasses Warning in the Preface section.

  2. Remove the lower radiator outlet hose at the coolant inlet pipe connection.
  3. Remove the upper radiator inlet hose at the coolant outlet housing connection.

    4. Note:  When attaching the lead away hose, make sure not to block the air bleed hose.

  4. Attach a lead away hose to the open end of the upper radiator hose.
  5. Attach a suitable piece of hose or adaptor between the flushing gun and the open end of the lower radiator hose.
  6. Connect and operate the flushing equipment as recommended by the manufacturer.

    7. Note: Make sure to apply air pressure gradually and not in excess of 130 kPa.

  7. Continue flushing until water from the lead away hose runs clean and clear.
  8. Install all disconnected hoses, ensuring that they are correctly position and securely clamped.
  9. Fill the cooling system. Refer to Cooling System Draining and Filling.
  10. Pressure test the cooling system. Refer to Cooling System Leak Testing.

Heater Hoses and Core

    Note: Do not use a chemical flush.

    Store used coolant in the correct manner, such as in a used engine coolant holding tank. Do not pour used coolant down a drain. Ethylene glycol antifreeze is a very toxic chemical. Do not dispose of coolant into the sewer system or ground water. This is illegal and ecologically unsound.

  1. Drain the cooling system. Refer to Cooling System Draining and Filling.

    2. Object Number: 1949721 Size: SH

    Note: Make a note of how the inlet and outlet hoses were removed for correct installation.

  2. Remove both heater hoses (1, 2) from their connections at the water pump.
  3. Direct the hose (1) that was connected to the water pump's rear-most connection into a suitable container.
  4. Attach the hose (2) from the front connection to the flushing gun.

    5. Note: Make sure to apply air pressure gradually and not in excess of 130 kPa.

  5. Connect and operate the flushing gun.

    6. Object Number: 1949721 Size: SH
  6. Install the heater hoses (1, 2), ensuring they are installed in the correct positions.
  7. Fill the cooling system. Refer to Cooling System Draining and Filling.
  8. Pressure test the cooling system. Refer to Cooling System Leak Testing.

Engine

    Note: Do not use a chemical flush.

    Store used coolant in the correct manner, such as in a used engine coolant holding tank. Do not pour used coolant down a drain. Ethylene glycol antifreeze is a very toxic chemical. Do not dispose of coolant into the sewer system or ground water. This is illegal and ecologically unsound.

  1. Drain the cooling system. Refer to Cooling System Draining and Filling.
  2. Detach the inlet hose. Refer to Radiator Inlet Hose Replacement.
  3. Detach the outlet hose. Refer to Radiator Outlet Hose Replacement.
  4. Remove the thermostat housing. Refer to Engine Coolant Thermostat Housing Replacement.
  5. Remove the thermostat. Refer to Engine Coolant Thermostat Replacement.
  6. Install the thermostat housing. Refer to Engine Coolant Thermostat Housing Replacement.

    7. Object Number: 1949735 Size: SH
  7. Remove the engine coolant air bleed hose (1) by releasing retaining hose clamp (2) and remove it from the radiator spigot (3) and temporarily plug the end of the hose.

    8. Object Number: 1949721 Size: SH

    Note: Make a note of how the inlet and outlet hoses were removed for correct installation.

  8. Remove the heater hoses (1, 2) from their connections at the water pump. Seal the pump connections by looping the water pump heater inlet connection to the outlet connection using a suitable piece of hose and two retaining clamps.
  9. Install a lead-away hose to the thermostat housing and a length of suitable hose between the water pump outlet fitting and the flushing gun.
  10. Connect and operate the flushing gun.
  11. Unplug the air bleed hose and continue flushing until the water runs clear.

    12. Object Number: 1949721 Size: SH
  12. Install the heater hoses (1, 2), ensuring they are installed in the correct positions.
  13. Install the thermostat. Refer to Engine Coolant Thermostat Replacement.
  14. Install the thermostat housing. Refer to Engine Coolant Thermostat Housing Replacement.

    15. Object Number: 1949735 Size: SH
  15. Attach the coolant air bleed hose (1) to the radiator spigot (3).
  16. Secure the coolant air bleed hose (1) with the retaining hose clamp (2)
  17. Attach the outlet hose. Refer to Radiator Outlet Hose Replacement.
  18. Attach the inlet hose. Refer to Radiator Inlet Hose Replacement.
  19. Fill the cooling system. Refer to Cooling System Draining and Filling.
  20. Pressure test the cooling system. Refer to Cooling System Leak Testing.