3B7S01031-0 Tohatsu CAP, THERMOSTAT

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, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products.Dispose of all fluids according to local regulations and mandates.
Shell and Tube Heat Exchanger
The interval for the maintenance of the shell and tube 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.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.Cleaning the Shell and Tube Heat Exchanger
Refer to the Disassembly and Assembly Manual for the engine.
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.Maximum air pressure at the nozzle must be less than 205 kPa (30 psi) for cleaning purposes.
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 the Service Manual for the procedure. For more information on cleaning the core, consult your Caterpillar dealer.Plate Type Heat Exchanger
The interval for the maintenance of the plate type 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 heat exchanger plates
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.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 of the heat exchanger and maintenance of the heat exchanger are required if the engine is overheating. Your Caterpillar dealer has the equipment and the personnel in order to measure the pressure drop across the heat exchanger.Consult your Caterpillar dealer or refer to the Service Manual for service information for the heat exchanger.Cleaning the Plate Type Heat Exchanger
Refer to the Disassembly and Assembly Manual for the engine. The heat exchanger must be disassembled in order to be cleaned. The Disassembly and Assembly Manual will contain instructions for cleaning the heat exchanger prior to reassembly. The following general guidelines are for cleaning a plate type heat exchanger. Refer to Table 2 for types of cleaners.
Do not use hydrochloric acid to clean stainless steel plates. Do not use hydrofluoric acid to clean titanium plates. Water that contains more than 300 ppm of chlorine should not be used to prepare cleaning solutions.Do not use Ketones such as Acetone and Methyletyketone.Do not use esters such as Ethylacetate and Butylacetate.Do not use Halogenated hydrocarbons such as Chlorothene and Carbon TetrachlorideDo not use Aromatics such as Benzene and Toluene.