Service Manual

ISB, ISBe and QSB (Common Rail [...] Coolant Thermostat
Section 8 - Cooling System - Group 08 Page 8-17
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Install
CAUTION
Always use the correct thermostat and do not operate
the engine without a thermostat installed. The engine
can overheat if operated without a thermostat
because the path of least resistance for the coolant is
through the bypass to the pump inlet. An incorrect
thermostat can cause the engine to overheat or run
too cold.
Install the thermostat into the thermostat housing.
NOTE: Make sure a new thermostat seal is installed on
the outer lip of the thermostat flange every time the
thermostat is installed.
NOTE: This stepblock does not apply to QSB5.9 engines
with keel cooling.
Install the water outlet connection and mounting
capscrews.
Tighten the capscrews.
Torque Value: 10 N•m [ 89 in-lb ]
CAUTION
Always use the correct thermostat and do not operate
the engine without a thermostat installed. The engine
can overheat if operated without a thermostat
because the path of least resistance for the coolant is
through the bypass to the pump inlet. An incorrect
thermostat can cause the engine to overheat or run
too cold.
NOTE: Make sure a new thermostat seal is installed on
the outer lip of the thermostat flange every time the
thermostat is installed.
On QSB5.9 marine engines with keel cooling, install the
thermostat into the water inlet connection of the
thermostat housing used with keel cooling.
Install the water outlet connection and tighten the
capscrews.
Torque Value: 24 N•m [ 18 ft-lb ]