WATER PUMP, THERMOSTAT & IDLER PULLEYS
IMPORTANT: Impeller to housing
clearance 4 and 8 vane pumps:
0.25 - 1.17 mm
(0.010 - 0.046 in.)
0.31 - 1.63 mm
(0.012 - 0.064 in)
Determine impeller to housing clearance as
With feeler gauges in place press impeller
until feeler gauges (2, Fig. 25) are snug.
Use a sleeve (1, Fig. 25) under press ram
as shaft will protrude slightly from impeller.
NOTE: Use an appropriate size feeler gauge
(0.97 mm [0.038 in.] ) for the 7 vane pump.
Using a new gasket, secure water pump to
crankcase front cover.
Install water pump pulley, fan and spacer, if
one was used.
The thermostat is used to control the temperature of the
engine coolant. It is located in a housing attached to the
cylinder head. The housing is arranged to return the
coolant to the radiator or to by-pass it depending on the
When the coolant is more than 82°C (180F), the
thermostat is actuated, becoming fully open at 94°
(202F). During this time, the coolant is directed by the
thermostat, in the thermostat housing, to flow to the top
water tank of the radiator for air cooling. Coolant in the
engine is replaced with coolant from the radiator bottom
tank to the water pump.
Remove the Thermostat as follows:
Disconnect the hose.
Remove the bolts and lock washers, then
remove the thermostat housing.
Remove the thermostat housing gasket and
CLEANING, INSPECTION AND REPAIR
Clean the Thermostat Housing as follows:
Wash the housing in solvent.
Dry with compressed air.
INSPECTION AND REPAIR
Inspect and Repair the Thermostat as follows:
Inspect for accuracy as follows:
Suspend the thermostat in a container of
water. DO NOT allow the thermostat to
touch the sides or bottom of the container.
Heat the container.
Measure the water temperature with a
thermometer suspended in container.
If the thermostat opening temperature is
6C (10F) above or below the 82C to
94°C (180F to 202F) rating, replace the
Visually inspect the housing for cracks and
burrs. Replace if necessary.
Inspect the housing seal for brittleness,
cracks or wear. Replace if necessary.
PRINTED IN UNITED STATES OF AMERICA