Disassembling The Coolant Pump; Inspecting The Coolant Pump - Yanmar 6LY3 series Service Manual

Coolant Pump Components and Functions
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Disassembling the Coolant Pump

NEVER disassemble the coolant pump. Replace
when defective.
When removing the coolant pump as an assembly
from the cylinder and cylinder head, replace the
cylinder inlet pipe O-ring.
When the coolant pump body and cylinder inlet
flange and / or coolant pump and pump plate are
disassembled, retighten pump mounting bolts to
the specified torque.
Coolant Pump Bolt Torque
6.9-10.0 N·m (0.7-1.1 kgf·m)
6LY3 Service Manual

Inspecting the Coolant Pump

Bearing Unit Inspection
Rotate the impeller. If the rotation is not smooth, or
an abnormal noise is heard or felt, replace the
pump as an assembly.
Impeller Inspection
Check the impeller blades. Replace if damaged,
corroded or if the impeller blade is excessively worn
due to contact with the pump body.
Coolant and Bypass Lines
Check the holes in the coolant and bypass lines,
clean out any dirt or other foreign matter and repair
as needed.
Coolant Pump Replacement
Replace the pump as an assembly if there is
excessive coolant leakage due to mechanical seal
or impeller seal wear.
Inspect Coolant Pump
Inspect the coolant pump body and flange, and
clean off scale and rust. Replace if corroded.
© 2007 Yanmar Marine International
COOLANT SYSTEM
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