Aerostar 2WD V6-245 4.0L (1990)
Water Pump: Testing and Inspection
After Repairs Operational Check
COOLING SYSTEM OPERATIONAL CHECK
IMPORTANT: Always verify the operation of the thermostat and cooling fan prior to driving the vehicle after a cooling system repair.
HOW
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With the cooling system filled with coolant and the radiator cap installed, start the engine and allow the coolant to warm up.
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The upper radiator hose should remain cool to the touch until the coolant within the engine block and head has reached the thermostat opening
temperature.
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The thermostat opening should be indicated by a rapid warm up of the upper radiator hose.
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If upper hose gradually warms up, the thermostat may be stuck open (assuming the engine is started cold)
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If the coolant temperature reaches the normal operating temperature (as indicated by the temperature gauge) before the upper hose becomes warm,
the engine should be turned off, and the cooling system allowed to cool down. The thermostat may be stuck closed and should be removed and
tested.
WARNING: Never remove a radiator cap while the engine is hot. Severe personal injury may result.
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After the cooling system has warmed up, turn off the engine, and verify the cooling fan clutch has engaged.
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The clutch should offer resistance when attempting to rotate the fan by hand.
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When the engine is cold the fan should spin freely on the clutch.
WHY
