SEAL 4W1055 - Caterpillar

The information from the sensors enables the electronic control module (ECM) to control the engine as efficiently as possible over a wide range of operating conditions.The sensors also enable the ECM to activate alarms, derates, and shutoffs in response to abnormal operation. The functions of the sensors are described below.
Illustration 1 g01096774
Right view
A 20 cylinder engine is shown. The sensors have the same locations on 16 cylinder engines.
(1) Pressure switch for the engine's coolant (inlet)
(2) Detonation sensor
(3) Electrohydraulic actuator's pressure switch
(4) Engine coolant temperature sensor
(5) Manifold air temperature sensor Pressure switch for the inlet of the coolant (1) - A pressure switch is located at the inlet for the engine jacket water. If the inlet pressure is too high, the switch will activate a shutdown. To observe the status of the switch, use the Caterpillar Electronic Technician (ET) to view the "Engine Coolant Pump Pressure" parameter.Detonation sensors (2) - The detonation sensors monitor the engine for mechanical engine vibrations. Each sensor monitors two cylinders. The sensor produces a voltage signal that is proportional to the engine detonation. If detonation occurs, the ECM can retard the ignition timing in order to reduce detonation. Refer to , "Ignition System". To observe the value of the output of the sensors, use Cat ET to view the "Cylinder #X Detonation Level". The "X" is the number for the particular cylinder.Electrohydraulic actuator's pressure switch (3) - The electrohydraulic actuator has a pressure switch for the oil supply. Insufficient oil pressure will activate an engine shutdown. To observe the status of the switch, use Cat ET to view the "Hydrax Oil Pressure Switch Status".Engine coolant temperature sensor (4) - The temperature sensor is located in the water temperature regulator housing. To monitor the coolant temperature, the element must be in contact with the coolant. Otherwise, the sensor will not function properly. A high coolant temperature will activate an alarm or a shutdown. A low coolant temperature will only activate an alarm. The trip points for the activation can be programmed with Cat ET. The engine can be restarted after a shutdown due to high engine coolant temperature. However, another shutdown will occur after one minute if the temperature remains high. To observe the value of the output of the sensor, use Cat ET to view the "Engine Coolant Temperature" parameter.Manifold air temperature sensor (5) - A sensor for monitoring the manifold air temperature is located in the inlet elbow for the number one cylinder head. Excessive manifold air temperature can activate an alarm or a shutdown during high load or low load operation. The trip points for activation can be programmed with Cat ET. To observe the value of the output of the sensor, use Cat ET to view the "Inlet Air Temperature" parameter.
Illustration 2 g01096853
Left view
A 20 cylinder engine is shown. The sensors have the same locations on 16 cylinder engines.
(6) Pressure sensor for unfiltered oil
(7) Pressure sensor for filtered oil
(8) Manifold air pressure sensor
(9) Engine coolant pressure sensor (outlet)
(10) Engine oil temperature sensor
(11) Humidity