Section 4 • Repair Procedures
REV A
4 - 14
AL8000HT Light Tower
Part No. 116478
September 2008
Isuzu 4LE1 Engine
5-1
Timing Adjustment
Complete information to perform this procedure is
available in the
Isuzu 4LE1 Workshop Manual
(Isuzu part number: IDE-2270).
Isuzu 4LE1 Workshop Manual
Terex part number
116166
5-2
Glow Plugs
How to Check the Glow Plugs
1 Disconnect the wiring and buss bar from the
glow plugs.
2 Connect the leads from an ohmmeter between
each glow plug terminal and ground.
Result: The resistance should be approximately
1
Ω
.
Result: The resistance is 0
Ω
or greater than
1
Ω
. The glow plug is faulty.
5-3
Coolant Temperature and
Oil Pressure Switches
The engine coolant temperature switch is a
normally open switch. The switch contacts close at
approximately 221°F / 105
°
C. If the coolant
temperature rises above the switch point, the
switch contacts close and the engine will shut off
to prevent damage. The engine will not start until
the temperature drops below the switch point.
Additionally a low collant level can cause the
coolant temperature switch to not work properly.
Make sure that the coolant system is at the proper
level.
The engine oil pressure switch is a normally closed
switch. The switch contacts open at approximately
14 psi / 0.96 bar. If the oil pressure drops below the
switch point, the contacts open and the engine will
shut off to prevent damage.
