Cooling System Flushing

Diesel engine coolant system flushing

 CAUTION

During filling, air must be vented from the engine coolant passages. The air vents through the “jiggle pin” openings to the top radiator hose and out the fill opening. Additional venting is provided for engines equipped with an aftercooler. Open the petcock during filling.

 NOTE: Adequate venting is provided for a fill rate of 19 liters/minute [5 U.S. Gallon/minute].

 Fill the system with a mixture of sodium carbonate and water (or a commercially available equivalent).

 NOTE: Use 0.5 kilogram [1.0 pound] of sodium carbonate for every 23 liters [6.0 U.S. gallons] of water.

    CAUTION

Do not install the radiator cap. The engine is to be operated without the cap for this process. 

Diesel engine coolant system flushing

Operate the engine for five minutes with the coolant temperature above 80°C [176°F].  Shut the engine off and drain the cooling system.

Fill the cooling system with clean water.

NOTES:

  • Be sure to vent the engine and aftercooler for complete filling. 
  • Do not install the radiator cap or the new coolant filter. 
  • If the water being drained is still dirty, the system must be flushed again until the water is clean. 

 

Coolant System Filling

The system has a design fill rate of 19 liters per minute [5 U.S. Gallons per minute].

 CAUTION

The system must be filled properly to prevent air locks.  During filling, air must be vented from the engine coolant passages. Be sure to open the petcock on the aftercooler for aftercooled engines.  Wait 2 to 3 minutes to allow air to be vented, then add mixture to bring the level to the top. Operate the engine for five minutes with the coolant temperature above 80°C [176°F].  Shut the engine off and drain the cooling system.    

  Use a mixture of 50 percent water and 50 percent ethylene glycol antifreeze to fill the cooling system.  4BTA and 6BTA engines use a jacket-water aftercooler. If a Charge Air Cooler is used, the coolant capacity is the same as the naturally aspirated or turbocharged only engines.

  CAUTION

Never use water alone for coolant. Damage from corrosion can be the result of using water alone for coolant.

  Install the pressure cap. Operate the engine until it reaches a temperature of 80°C [180°F], and check for coolant leaks.  Check the coolant level again to make sure the system is full of coolant, or that the coolant level has risen to the hot level in the recovery bottle on the system, if so equipped.