Service Manual

ISB, ISBe and QSB (Common Rail [...] Coolant Thermostat Housing
Section 8 - Cooling System - Group 08 Page 8-21
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Leak Test
The engine thermostat and thermostat seal must operate
properly in order for the engine to operate in the most
efficient heat range. Overheating or overcooling will
shorten engine life.
Fabricate a test fixture to seal all of the water connections
except the outlet port to the keel cooler and the inlet port
of the thermostat housing.
On the outlet port to the keel cooler (1), install a hose long
enough to reach a remote, dry container to collect any
water. Place the open end of the hose in the dry
container.
Connect a filtered tap water hose to the inlet port (2) of
the thermostat housing with the pressure regulated to 152
kPa [22 psi] of filtered tap water.
Apply 152 kPa [22 psi] of water pressure to the thermostat
housing for 1 minute.
The maximum allowable leakage is 100 cc [3.4 fl oz] per
minute.
If more than 100 cc [3.4 fl oz] of coolant is collected, the
thermostat or thermostat seal is leaking and must be
replaced. Refer to Procedure 008-016