23161-ZV5-000 Honda RUBBER, SEAL (Honda Code 3702701).

Drain the Cooling System
Stop the engine and allow the engine to cool. Ensure that the engine will not start when the cooling system is drained.
Loosen the cooling system filler cap slowly in order to relieve any pressure. Remove the cooling system filler cap.
Illustration 1 g00130652
Location of the cooling system drain valves or drain plugs on the water pumps
(1) Jacket water pump
(2) Aftercooler and oil cooler pump
Illustration 2 g00475784
Location of the drain plug (jacket water) for 3606 and 3608 Engines
Illustration 3 g00475850
Location of the drain plugs (jacket water) for 3612 and 3616 Engines
Open the cooling system drain valves (if equipped). Remove the cooling system drain plugs. Allow the coolant to drain.
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 Caterpillar Dealer Service Tools Group:Outside U.S.A. (309) 675-6277
Inside U.S.A. 1-800-542-TOOL
Inside Illinois 1-800-541-TOOL
Canada 1-800-523-TOOL
CSTG COSA Geneva, Switzerland 41-22-849 40 56
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 in order to remove any debris.
Close the cooling system drain valves (if equipped). 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 .5 L (1 pt) of cleaner per 15 L (4 US gal) of the cooling system capacity. Install the cooling system filler cap.
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. Loosen the cooling system filler cap slowly in order to relieve any pressure. Remove the cooling system filler cap. Open the cooling system drain valves (if equipped). 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 cooling system drain valves (if equipped). Clean the cooling system drain plugs and install the cooling system drain plugs. 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 in order to remove any debris.
Close the cooling system drain valves (if equipped). Clean the cooling system drain plugs and install the cooling system drain plugs.
Fill the cooling system with a mixture of clean water and Caterpillar Fast Acting Cooling System Cleaner. Add .5 L (1 pt) of cleaner per 3.8 to 7.6 L (1 to 2 US gal) of the cooling system capacity. Install the cooling system filler cap.
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. Loosen the cooling system filler cap slowly in order to relieve any pressure. Remove the cooling system filler cap. Open the cooling system drain valves (if equipped). 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 cooling system drain valves (if equipped). Clean the cooling system drain plugs and install the cooling system drain plugs. Fill the Cooling System
Fill the cooling system no faster than 19 L (5 US gal) per minute to avoid air locks.
Note: For information about the proper coolant to use, see this Operation and Maintenance Manual, "Refill Capacities and Recommendations" (Maintenance Section). For the capacity of the cooling system, see this Operation and Maintenance Manual, "Refill Capacities and Recommendations" (Maintenance Section).