31620-ZV1-A01 Honda RECTIFIER ASSY., REGULATOR (Honda Code 3749181).

Keep all parts clean from contaminants.Contaminants may cause rapid wear and shortened component life.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, NENG2500, "Cat Dealer Service Tool Catalog" or refer to Special Publication, PECJ0003, "Cat Shop Supplies and Tools Catalog" for tools and supplies suitable to collect and contain fluids on Cat products.Dispose of all fluids according to local regulations and mandates.
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 systemOperating 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 outletAn 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.
Drain the heat exchanger.
Remove the heat exchanger.
Turn the heat exchanger core upside-down in order to remove debris.
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.
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.
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)
(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.
Steam clean the core in order to remove any residue. Flush the tubes of the heat exchanger core. Remove any other trapped debris.
Wash the core with hot, soapy water. Rinse the core thoroughly with clean water.
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.
Dry the core with compressed air. Direct the air in the reverse direction of the normal flow.
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.
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.