JOINT AS-TUBE 3N2451 - Caterpillar

D330C, D333C, D348, D349, D353, D379, D398, D399, 3304, 3306, 3406, 3408, 3412, 3512 Industrial Engines;
3512 Marine Engines;
D379, D398, D399, 3512 Generator Set Engines Equipped With 5N5739 Or 5N5740 Electric Water HeatersDescription of Change: Two improvements have been made to element assemblies used in 5N5739 (120 Volt) and 5N5740 (240 Volt) Jacket Water Heaters (Electric) for the above engines. The first change moves the element body nearer the coolant inlet, so coolant will be completely around the element at all times. Formerly, it was possible for a part of the element to be out of the coolant under some conditions. This can cause element damage. The second change is the use of terminal studs with nuts for the wire connections on the element. Formerly, short wires were mechanically connected into the element, and extended out for connections to be made. The mechanical connections became hot after a period of time, and caused either a high resistance or an open circuit. This made it necessary to install a new element. See the topic "Installation" for the correct procedure to install a new element.Adaptable As: Direct replacement. The part numbers of the element assemblies did not change. The chart shows the part numbers of the thermostat and the elements for each heater. The same thermostat is used for both heaters, but be sure to check the element for the correct voltage. If a 240 Volt element is connected to a 120 Volt circuit, it will not heat correctly; if a 120 Volt element is connected to a 240 Volt circuit, it will cause immediate element and/or thermostat failure. INSTALLATION: The improved elements can be installed in earlier heaters. A 1 3/4"-3/4" drive socket is needed, and an impact wrench can be used if necessary to remove the old element. Use 5P3413 Sealant on the threads of the new element, and tighten to 110 N m (80 lb ft) torque. Do not use an impact wrench to tighten the new element. Leakage of coolant around the element threads can cause corrosion and/or electrical problems. Use 10 Gauge wire with terminal connectors, and be sure all electrical connections are clean and tight. Good electrical connections are important to keep resistance at a minimum and to prevent overheating (high temperature) damage to the connections. Connect the power source wires to one terminal of the thermostat and one terminal of the element. Connect a separate 10 Gauge wire between the other two terminals (one on the thermostat and one on the element).
After installation is complete and the heater is filled with coolant, check for coolant leakage before the electrical power is turned on. Never turn on electrical power to the heater when it is not connected into the cooling system and filled with coolant.