74832 Mercruiser PLUG, CYLINDER HEAD

Drain the Cooling System
Stop the engine and allow the engine to cool. Close the water inlet for the separate circuit aftercooler (if equipped). Ensure that the engine will not start when the cooling system is drained.
Loosen the radiator filler cap slowly to relieve any pressure. Remove the radiator filler cap.Note: For the location of the coolant drains, see the service literature that is provided by the OEM of the locomotive.
Refer to this Operation and Maintenance Manual, Model Views for typical drain plug locations.Note: If the engine has a jacket water heater, drain the coolant from the heater.Open the coolant drain. Remove cooling system drain plugs. Allow the coolant to drain.Note: If the engine has a separate circuit aftercooler, follow the recommended procedure for draining the aftercooler.
Remove the aftercooler drain plugs. Allow the coolant to drain.
Clean the aftercooler drain plugs. Install the aftercooler drain plugs.
Dispose of used engine coolant properly or recycle. Various methods have been proposed to reclaim used coolant for reuse in engine cooling systems. The full distillation procedure is the only method acceptable by Caterpillar to reclaim the used coolant.
For information regarding the disposal and the recycling of used coolant, consult your Cat dealer or consult Cat Dealer Service Tools:Outside U.S.A. (309) 675-6277
Inside U.S.A. 1-800-542-8665
Inside Illinois 1-800-541-8665
Canada 1-800-523-8665
Clean the Cooling System
Use of commercially available cooling system cleaners may cause damage to cooling system components. Use only cooling system cleaners that are approved for Caterpillar engines.
After the cooling system has been drained, flush the cooling system with clean water to remove any debris.
Close the cooling system drain. Clean the cooling system drain plugs and install the cooling system drain plugs.
Fill the cooling system no faster than 19 L (5 US gal) per minute to avoid air locks.
Fill the cooling system with a mixture of clean water and Cat Fast Acting Cooling System Cleaner. Add 0.5 L (1 pt) of cleaner per 15 L (4 US gal) of the cooling system capacity. Install the radiator filler cap.
Open the water inlet for the separate circuit aftercooler (if equipped). Start the engine. Operate the engine for a minimum of 30 minutes with a coolant temperature of at least 82 °C (180 °F).
Stop the engine and allow the engine to cool. Close the water inlet for the separate circuit aftercooler (if equipped). Loosen the radiator filler cap slowly to relieve any pressure. Remove the radiator filler cap. Open the coolant drain. Remove the cooling system drain plugs. Allow the water to drain.
Improper or incomplete rinsing of the cooling system can result in damage to copper and other metal components.To avoid damage to the cooling system, make sure to completely flush the cooling system with clear water. Continue to flush the system until all signs of the cleaning agent are gone.
Flush the cooling system with clean water until the water that drains is clean. Close the coolant drain. Clean the cooling system drain plugs and install the cooling system drain plugs. Open the water inlet for the separate circuit aftercooler (if equipped).Cleaning a Cooling System that has Heavy Deposits or Plugging
Note: For the following procedure to be effective, there must be an active flow through the cooling system components.
After the cooling system has been drained, flush the cooling system with clean water to remove any debris.
Close the coolant drain. Clean the cooling system drain plugs and install the cooling system drain plugs.
Fill the cooling system no faster than 19 L (5 US gal) per minute to avoid air locks.
Fill the cooling system with a mixture of clean water and Cat Fast Acting Cooling System Cleaner. Add 0.5 L (1 pt) of cleaner per 3.8 L to 7.6 L (1 to 2 US gal) of the cooling system capacity. Install the radiator filler cap.
Open the water inlet for the separate circuit aftercooler (if equipped). Start the engine. Operate the engine for a minimum of 90 minutes with a coolant temperature of at least 82 °C (180 °F).
Stop the engine and allow the engine to cool. Close the water inlet for the separate circuit aftercooler (if equipped). Loosen the radiator filler cap slowly to relieve any pressure. Remove the radiator filler cap. Remove the cooling system drain plugs. Open the coolant drain. Allow the water to drain.
Improper or incomplete rinsing of the cooling system can result in damage to copper and other metal components.To avoid damage to the cooling system, make sure to completely flush the cooling system with clear water. Continue to flush the system until all signs of the cleaning agent are gone.
Flush the cooling system with clean water until the water that drains is clean. Close the coolant drain. Clean the cooling system drain plugs and install the cooling system drain plugs.Fill the Cooling System
Note: For information about the proper coolant to use, see Special Publication, SEBU6251, "Caterpillar Commercial Diesel Engine Fluids Recommendations". For the capacity of the cooling system, see this Operation and Maintenance Manual, "Refill Capacities and Recommendations" (Maintenance Section).
Fill the cooling system no faster than 19 L (5 US gal) per minute to avoid air locks.
Fill the cooling system with a antifreeze/coolant solution. After filling the cooling system, do not install the radiator filler cap.
Open the water inlet for the separate circuit aftercooler (if equipped). Start the engine. Operate the engine to purge the air from the cavities of the engine block. Allow the coolant to warm and allow the coolant level to stabilize. Stop the engine.
Check the coolant level. Maintain the coolant to the proper level on the sight gauge (if equipped). If a sight gauge is not equipped, maintain the coolant within 13 mm (0.5 in) below the bottom of the filler pipe.
Clean the radiator filler cap. Inspect the gaskets of the radiator filler cap. If the gaskets of the radiator filler cap are damaged, discard the old radiator filler cap and install a new radiator filler cap. If the gaskets of the radiator filler cap are not damaged, use a 9S-8140 Pressurizing Pump to pressure test the radiator filler cap. The correct pressure is