G3500 Generator Sets Caterpillar

Clean the cooling system before the recommended maintenance interval if the following conditions exist:

• The engine overheats frequently.

• Foaming is observed.

• The oil has entered the cooling system and the coolant is contaminated.

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NOTICE
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.

Draining 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.

For information regarding the disposal and the recycling of used coolant, consult your Caterpillar dealer or consult Caterpillar Dealer Service Tool Group:

Outside Illinois 1-800-542-TOOL
Inside Illinois 1-800-541-TOOL
Canada 1-800-523-TOOL

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NOTICE
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.

Draining the Jacket Water

1. Loosen the cooling system filler cap slowly in order to relieve any pressure. Remove the cooling system filler cap.
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   Illustration 1	g00760198
   Locations of the drain plugs (1) Oil cooler (2) Cylinder block

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   Illustration 2	g00775179
   (3) Drain plug in the elbow before the water pump on the front of the engine

   Note: If the engine is equipped with a jacket water heater, a water line will be installed in the location of drain plug (2).

2. Open the cooling system drain valves (if equipped). If the cooling system is not equipped with drain valves, remove drain plugs (1), (2), and (3).

   Drain the coolant from the bottom of the jacket water heater (if equipped).

Draining the Separate Circuit

Illustration 3	g00760199
(1) Vent plug on the aftercooler

A heat exchanger or a radiator is provided by the customer for the separate circuit aftercooler. Each side of the aftercooler has vent plug (1). Remove the vent plugs. Remove the cooling system filler cap and drain the water from the heat exchanger or the radiator.

Clean the Cooling System

1. After the cooling system has been drained, flush the cooling system with clean water in order to remove any debris.

2. Close the cooling system drain valves (if equipped). Clean the drain plugs and install the drain plugs.
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   NOTICE
   Fill the cooling system no faster than 19 L (5 US gal) per minute to avoid air locks.

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   Illustration 4	g00760199
   (1) Vent plug on the aftercooler

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   NOTICE
   If the aftercooler circuit has been drained, the vent plug must be opened to allow the aftercooler to fill properly. Failure to do this will cause an air lock resulting in engine damage.

3. When the separate circuit is filled, be sure to remove vent plugs (1) from the aftercooler.

4. Fill the cooling system with a mixture of clean water and Caterpillar Fast Acting Cooling System Cleaner. Add .5 L (1 pint) of cleaner per 15 L (4 US gal) of the cooling system capacity. Install the cooling system filler cap. Install vent plugs (1).

5. Start the engine. Operate the engine for a minimum of 30 minutes with a coolant temperature of at least 82 °C (180 °F).

6. Stop the engine and allow the engine to cool. For the jacket water and the separate circuit, 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. Remove the vent plugs from the aftercooler.
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   NOTICE
   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.

7. 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.

1. After the cooling system has been drained, flush the cooling system with clean water in order to remove any debris.

2. Close the cooling system drain valves (if equipped). Clean the drain plugs and install the drain plugs.

3. Remove the vent plugs from the aftercooler.

4. Fill the cooling system with a mixture of clean water and Caterpillar Fast Acting Cooling System Cleaner. Add .5 L (1 pint) 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. Install vent plugs into the aftercooler.

5. Start the engine. Operate the engine for a minimum of 90 minutes with a coolant temperature of at least 82 °C (180 °F).

6. 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. Remove the vent plug from the aftercooler. Allow the water to drain.
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   NOTICE
   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.

7. 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

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NOTICE
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, and for the capacity of the cooling system, see this Operation and Maintenance Manual, "Refill Capacities and Recommendations" (Maintenance Section).

1. Remove the vent plugs from the aftercooler.

2. Fill the cooling system with coolant/antifreeze. Install the vent plugs for the aftercooler. Do not install the cooling system filler cap yet.

3. 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.

4. 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 (.5 inch) below the bottom of the filler pipe.

5. 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, discard the old cooling system filler cap and install a new cooling system filler cap.

6. Start the engine. Inspect the cooling system for leaks and for proper operating temperature.