Coolant System Flushing

For Reference

a PROPER coolant flush at home, revisited by SATURNFAN Dn400Man

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 the cap from a hot system. Allow the system to cool, then slowly remove the cap.

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.

1. The cooling system holds approximately two gallons of coolant.
Prepare a mixture of Calgon® automatic dishwasher detergent or equivalent, and water at the ratio of two ounces (dry measure) to 3.8 liters (1 gal) of water.
2. The vehicle has two drains: one located in the lower right hand side of the radiator and the other one located directly under the thermostat housing.
Remove the coolant surge tank 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 5 minutes.
6. Drain the cooling system.
7. Repeat Steps 4-6.
8. Fill the cooling system with clean water.
9. Let the engine run 5 minutes.

Notice

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

10. Drain the cooling system completely.
11. Install the new engine thermostat. Refer to Thermostat Replacement .
12. Install the new water pump. Refer to Water Pump Replacement .
13. Install the cylinder block drain plug.
Tighten

Tighten the cylinder block drain plugs to 35 N·m (26 lb ft).

14. Close the 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 the engine until the upper radiator hose is hot, then add additional coolant, if needed, to bring the level to the FULL COLD range.
17. Install the coolant surge tank cap and check for leaks.