20220 Mercury NUT, STEERING HANDLE BRACKET SCREW

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 g02232739
Locations of the drain plugs (1) Oil cooler (2) Jacket water drain (3) SCAC water drain
Open the cooling system drain valves (if equipped). If the cooling system is not equipped with drain valves, remove drain plugs (1), (2), (3). 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 Caterpillar dealer or consult Dealer Service Tools Group:Outside Illinois: 1-800-542-TOOLInside Illinois: 1-800-541-TOOLCanada: 1-800-523-TOOLClean the Cooling System
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 drain plugs and install the drain plugs.
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.
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 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) or remove the drain plugs.
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.
Allow the water to drain. Flush the cooling system with clean water until the water that drains is clean. Close the cooling system drain valves (if equipped). Clean the drain plugs and install the 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 drain plugs and install the drain plugs. See Illustration 1.
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) or remove the drain plugs. See Illustration 1. 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 drain plugs and install the 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).
Fill the cooling system with coolant/antifreeze. Do not install the cooling system filler cap.
Start the engine. Operate the engine in order 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 inch) below the bottom of the filler pipe.
Clean the cooling system filler cap. Inspect the gaskets of the cooling system filler cap. If the gaskets of the cooling system filler cap are damaged, cap and install a new cap. If the gaskets of the cooling system filler cap are not damaged, use a 9S-8140 Pressurizing Pump in order to pressure test the cap. The correct pressure is stamped on the face of the cooling system filler cap. If the cooling system filler cap does not maintain the correct pressure, install a new cooling system filler cap.
Start the engine. Inspect the cooling system for leaks and for proper operating temperature.