BOLT 3B7614 - Caterpillar

When an alarm is activated, corrective measures must be taken before the situation becomes an emergency in order to avoid possible engine damage.
Always determine the cause of the engine shutdown. Make necessary repairs before attempting restarting the engine.
Overspeed Shutoff
Magnetic pickup (1), mounted in the flywheel housing (2).A magnetic pickup mounted in the flywheel housing measures the engine speed by sensing the passage of the flywheel ring gear teeth. Should the engine speed increase above the overspeed setting (118 percent of rated engine speed), the magnetic pickup will sense the overspeed and send a signal to the GSC. The GSC activates both the fuel shutoff solenoid and the air shutoff (if equipped).Both the GSC and the air shutoff (if equipped) must be reset after an overspeed shutoff. The cause of the overspeed should be determined before the engine is restarted.Air Shutoff
The air shutoff is an optional attachment. The air shutoff is an electrical device which is actuated by an overspeed shutoff or by the use of the emergency stop pushbutton (ESBP). Both the GSC and the air shutoff (if equipped) must be reset before the engine can be restarted. The cause of the shutoff should be determined before the engine is restarted.
Turn the ECS to the OFF/RESET position in order to reset the GSC.Oil Pressure Sending Unit
Oil pressure sending unit.The oil pressure sending unit is mounted on the side of the engine. Low oil pressure can activate an alarm or shutoff. No resetting is required.Water Temperature Sending Unit
Water temperature sending unit.The water temperature sending unit is located in the cylinder head. High or low water temperature can activate an alarm or shutoff. No resetting is required.
The sensing element must be submerged in the coolant to operate. Be sure to have an adequate water supply in the jacket water system, or engine damage could result.
Coolant Loss Sensor (If Equipped)
The optional coolant loss sensor is usually mounted near the top of the engine expansion tank or radiator. The sensor detects when the coolant level is below a preset minimum level.
Typical coolant loss sensor (1), mounted near the top of a radiator (2).If the coolant level drops below the minimum level, the coolant loss sensor may activate an alarm or cause a shutoff in order to avoid engine overheating or possible engine damage. Coolant must be added to the radiator in order to clear or reset the condition.Shutoff and Alarm System Testing
Most control panels are equipped with a lamp test switch. Turn the switch to ON position to check indicator lights for proper operation. Replace defective or burnt bulbs immediately.
During testing, abnormal operating conditions must be simulated. Perform the tests correctly to prevent possible damage to the engine.
The Engine Protective Devices should be tested every 1000 service hours or twice a year for proper operation by authorized service personnel.Abnormal operating conditions must be simulated which could cause engine damage if the tests are performed incorrectly. Refer to the Service Manual or consult with your Caterpillar dealer for the testing procedures.