Do not change the coolant until you read and understand the material in the Cooling System Specifications section in this manual.
If the Diesel Engine Antifreeze/Coolant (DEAC) is dirty or if you observe any foaming in the cooling system, drain the coolant before the recommended interval.
It is important to replace the water temperature regulator in order to avoid any unexpected failure of the water temperature regulator. This is a good preventive maintenance practice that reduces the chances of unscheduled downtime. Failure to replace the water temperature regulator on a regularly scheduled basis could cause severe engine damage.
Note: If you are only replacing the water temperature regulator, drain the coolant from the cooling system so that the level of the coolant is below the water temperature regulator housing.
Always operate AVSpare Engines with a water temperature regulator because these engines have a shunt design cooling system.
Note: Water temperature regulators can be reused if the water temperature regulators meet certain test specifications. The tested water temperature regulators must not be damaged and the tested water temperature regulators must not have an excessive buildup of deposits.
- Stop the engine and allow the engine to cool.
- Slowly remove the cooling system pressure cap in order to relieve pressure.
- Open the drain valve that is under the radiator. Allow the coolant to drain into a suitable container.
Note: Always discard drained fluids according to local regulations.
- Close the drain valve. Fill the cooling system with clean water and with a 6 to 10% concentration of cooling system cleaner.
- Start the engine. Run the engine for 90 minutes.
- Stop the engine. Drain the cleaning solution.
- Flush the cooling system with water until the draining water is transparent.
- Close the drain valve.
- Add the coolant solution. Refer to Operation and Maintenance Manual, "Capacities (Refill)".
- Remove the cooling system pressure cap. Start the engine and run the engine. Leave the pressure cap off until the water temperature regulator opens and the coolant level stabilizes.
- Maintain the coolant level within 13 mm (.5 inch) of the bottom of the filler pipe.
- Install the cooling system pressure cap.
- Stop the engine.