KIT-GASKET 3925540 - Caterpillar

Heat Exchanger Cooling
Refer to Heat Exchanger Cooling in this manual.The raw water flows through the tubes of the heat exchanger while the engine coolant (jacket water) is circulated through the heat exchanger shell across the tubes by the jacket water pump.For a given jacket water flow rate, the performance of a heat exchanger depends on both the raw water flow rate and the differential of the jacket water temperature out of the engine into the heat exchanger tubes.The heat exchanger should be selected to accommodate the raw water temperature and flow rate needed to keep the temperature DIFFERENTIAL of the jacket water below 8.3°C (15°F) at maximum engine heat rejection.Thermostats must be retained in the jacket water system to assure that the temperature of the jacket water coolant returned to the engine is a minimum of 79°C (174°F).Heat exchangers should be sized to accommodate a heat rejection rate approximately ten percent greater than the tabulated engine heat rejection. Refer to the Technical Marketing Information (TMI) system.Keel Cooling
Refer to Keel Cooling in this manual.A keel cooler is an outboard heat exchanger which is built as part of or attached to the submerged portion of the hull. The heated engine coolant (jacket water) is circulated through the keel cooler by the jacket water pump.Materials used in cooler construction, conditions of waters in which the vessel will operate and service life expectancy will influence the size selection of the cooler.The keel cooler materials must be compatible with materials used in the vessel's hull to prevent galvanic corrosion.A cooler may have to operate at its maximum capacity at zero hull speed as in the case of an auxiliary generator set operating while the vessel is in port.To determine the size of the keel cooler, the thermal resistance to heat transfer of the cooler material, the internal and external water flow rates, and the internal and external surface corrosion factors must be taken into account.Normal deterioration of the cooler's inner and outer surfaces in the form of rust, scale and pitting progressively reduce a keel coolers effectiveness over a period of time.Expansion Tanks
Refer to Expansion Tanks and Determining Expansion Tank Minimum Volume Requirements in this manual.The size of the expansion tank will depend on the type of cooling system selected.A keel cooling system will require a larger expansion tank due to the additional volume of water in the piping and keel cooler.A heat exchanger cooling system will need a smaller expansion tank due to the proximity of the heat exchanger to the engine and from efficiencies of a pressurized raw water system.The engine jacket water volume for the 3406 marine compact package is 36.2 L (9.40 U.S. gal).Shunt Line
There must be a shunt line and a vent line from the engine to the expansion tank. The shunt line should be a minimum 25.4 mm (1.00 in) Inside Diameter (ID) line running from the bottom of the expansion tank to the jacket water pump inlet elbow.Refer to 3406 Marine Engine Specifications in this manual.Vent