Chapter 2
NAME OF PARTS
2-4
Engine Protection Devices
The engine protection devices activate an alarm when an abnormality occurs in the engine in order to protect
the engine and prevent serious problems and accidents. When a protection device is activated, stop the
engine, examine the cause of the abnormality, and take corrective measures.
If the cause of the problem is unknown, contact a Mitsubishi dealer.
Protection devices installed on the engine and their types (setting values) and shapes vary depending on the
engine specifications. The following describes the typical protection devices installed in a Mitsubishi engine.
Oil Pressure Switch
The oil pressure switch turns on and generates an
alarm when the pressure of engine lubricating oil drops
below the preset level. The switch is activated when the
oil pressure becomes the entire engine speed range.
Oil Filter Alarm Switch
The oil filter alarm switch turns on and generates an
alarm when oil filters become clogged.
The switch is activated when the pressure difference
before and after oil filters reaches the limit.
Immediately replace to new oil filter when the alarm is
generated and at the same time replace the engine oil.
Thermo Switch
A thermo switch is installed to avoid overheating.
The thermo switch generates alarm sound when the
coolant temperature reaches specified level.
Oil
pressure
switch
fig.2-9 Oil pressure switch
Oil filter alarm switch
fig.2-10 Oil filter alarm switch
Thermo switch
fig.2-11 Thermo switch
