C12 Marine Engines Caterpillar

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Personal injury can result from hot coolant, steam and alkali. At operating temperature, engine coolant is hot and under pressure. The heat exchanger and all lines to heaters or the engine contain hot coolant or steam. Any contact can cause severe burns. Remove the filler cap slowly to relieve pressure only when the engine is stopped and the filler cap for the heat exchanger is cool enough to touch with your bare hand. Cooling System Conditioner contains alkali. Avoid contact with skin and eyes.

The interval for the maintenance of the heat exchanger depends on the operating environment of the vessel and on the operating time. The sea water that is circulated through the heat exchanger and the amount of operating time of the vessel affects the following items:

• Cleanliness of the tubes for the heat exchanger

• Effectiveness of the heat exchanger system

Operating in water that contains the following will adversely affect the heat exchanger system: silt, sediment, salt and algae. In addition, intermittent use of the vessel will adversely affect the heat exchanger system.

Inspect

The following items indicate that the heat exchanger may require cleaning:

• Increased coolant temperature

• Engine overheating

• Excessive pressure drop between the water inlet and the water outlet

An operator that is familiar with the normal operating temperature of the coolant can determine when the coolant temperature is out of the normal range. Inspection and maintenance of the heat exchanger are required if the engine is overheating.

Clean

Remove the heat exchanger. Refer to the Disassembly and Assembly Manual, "Heat Exchanger - Remove" for the procedure.

1. Drain the heat exchanger.

2. Remove the heat exchanger.

3. Turn the heat exchanger core upside-down in order to remove debris.
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   NOTICE
   Do not use a high concentration of caustic cleaner to clean the core. A high concentration of caustic cleaner can attack the internal metals of the core and cause leakage. Only use the recommended concentration of cleaner.

4. Back flush the core with cleaner.

   Caterpillar recommends the use of Hydrosolv liquid cleaner. Table 1 lists Hydrosolv liquid cleaners that are available from your Caterpillar dealer.

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   Table 1

   Hydrosolv Liquid Cleaners(1)
   Part Number	Description	Size
   1U-5490	Hydrosolv 4165	19 L (5 US gallon)
   174-6854	Hydrosolv 100	19 L (5 US gallon)

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   (1)	Use a two to five percent concentration of the cleaner at temperatures up to 93°C (200°F). Refer to Application Guide, NEHS0526 or consult your Caterpillar dealer for more information.

5. Steam clean the core in order to remove any residue. Flush the tubes of the heat exchanger core. Remove any other trapped debris.

6. Wash the core with hot, soapy water. Rinse the core thoroughly with clean water.
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   Personal injury can result from air pressure. Personal injury can result without following proper procedure. When using pressure air, wear a protective face shield and protective clothing. The maximum air pressure for cleaning purposes must be reduced to 205 kPa (30 psi) when the air nozzle is deadheaded.

7. Dry the core with compressed air. Direct the air in the reverse direction of the normal flow.

8. Inspect the core in order to ensure cleanliness. Pressure test the core. Many shops that service radiators are equipped to perform pressure tests. If necessary, repair the core.

9. Install the heat exchanger. Refer to Disassembly and Assembly, "Heat Exchanger - Install" for the procedure.

For more information on cleaning the core, consult your Caterpillar dealer.