Flushing the Cooling System

When the engine's cooling system becomes contaminated, it should be flushed thoroughly to remove the contaminants before the engine is seriously damaged. One source of contamination that is damaging to the engine if not corrected immediately is a cracked oil gallery. With a cracked oil gallery, oil will be forced into the cooling system while the engine is operating, and when it is stopped, coolant will leak into the lubricating system. If mixed with oil in the crankcase, this antifreeze forms a varnish which quickly immobilizes moving engine parts.
To remove such contaminants from the engine, both the cooling system and the lubrication system must be thoroughly flushed after the engine is repaired.

CAUTION: DO NOT REMOVE CAP OR OPEN COOLING SYSTEM DRAINS FROM A HOT SYSTEM. ALLOW SYSTEM TO COOL FIRST.

If the engine has had a failure resulting in the contamination of the cooling system with lubricating oil, or a substance other than a recommended antifreeze has been added, the following procedure is recommended:
^ The cooling system holds approximately two gallons of coolant.





1. Prepare a mixture of Calgon or equivalent (automatic dishwasher detergent), and water at the ratio of two ounces (dry measure) to 3.8 Liters (1 gal.) of water.
^ The vehicle has two drains: (1) one located in the lower right hand side of the radiator and the other (2) located directly under the thermostat housing.
2. Remove coolant recovery reservoir cap and drain the cooling system.





3. Remove the engine thermostat to permit the Calgon or equivalent and water mixture to circulate through the engine and the radiator.





4. Fill the cooling system with the Calgon or equivalent solution.
5. Run the engine for five minutes.
6. Drain the cooling system.
7. Repeat Steps 4 through 6.
8. Fill the cooling system with clean water.
9. Let the engine run five minutes.
10. Drain the cooling system completely.

NOTICE: If cooling system has been contaminated by oil, replacement of the thermostat and water pump is required.

11. Install new engine thermostat (refer to "Thermostat Inlet Housing and Element Installation").
12. Install new water pump (refer to "Water Pump Removal and Installation").
13. Install cylinder block drain plug.
Torque: 35 Nm (26 ft. lbs.)
14. Close radiator drain plug.

IMPORTANT: The vehicle must be level when filling with coolant.





15. Fill the system to the FULL COLD range with coolant. Use a 50/50 solution of Dex-Cool antifreeze and clean water.
16. Run engine until upper radiator hose is hot, then add additional coolant, if needed, to bring the level to the FULL COLD range.
17. Install coolant recovery reservoir cap and check for leaks.