SEAL 9J1797 - Caterpillar

Illustration 1 g00996133
Flow of engine oil during operation of the prelube pump (typical example)
(1) Box for the oil pressure switch
(2) Box for the relay
(3) Prelube pump motor
(4) Prelube pump The prelube pump is an option which provides lubrication for the engine prior to start-up. The service life of the engine is extended because of reduction in the opportunity of wear from the contact of dry moving parts.Illustrations 1 and 2 are typical examples. Several options are available for the prelubrication according to the needs of the customer. The electrical power supply, the wiring, and the electrical controls are provided by the customer.The customer provides the wiring and an electrical power source for the normally closed oil pressure switch in box (1). Customer supplied wiring connects the switch to a relay coil in box (2). Electrical power to the relay coil closes the relay contacts. The electrical power supply for the prelube pump motor (3) is routed through the relay contacts. The motor operates pump (4).The pump draws engine oil from the oil pan. The oil is pumped upward into the oil cooler's inlet elbow. The oil circulates normally through the engine.A hose is connected from the main oil gallery in the cylinder block to the oil pressure switch in box (1). When the engine oil pressure rises to the pressure rating of the oil pressure switch, the switch opens. This interrupts the electrical power supply to the relay coil and the relay contacts open. This interrupts the electrical power supply to the prelube pump motor. The pump stops.
Illustration 2 g01024481
Typical schematic for an electric prelube pump
Illustration 2 is a typical schematic for the described electric prelube pump. Notice that the relay has one pair of unused contacts. The customer could use those contacts to activate a lamp or an indicator. The schematic is only a reference. The customer determines the function of the relay and the routing of the wiring.