Durango 2WD V8-4.7L VIN N (2001)
The 4.7L engine uses an internal water/coolant bypass system. The design uses galleries in the timing chain cover to circulate coolant during engine
warm-up preventing the coolant from flowing through the radiator. The thermostat uses a stub shaft located at the rear of the thermostat to control flow
through the bypass gallery.
OPERATION-WATER PUMP
A centrifugal water pump circulates coolant through the water jackets, passages, intake manifold, radiator core, cooling system hoses and heater core,
this coolant absorbs the heat generated when the engine is running. The pump is driven by the engine crankshaft via a drive belt.
OPERATION-WATER PUMP BYPASS
When the thermostat is in the closed position the bypass gallery is not obstructed allowing 100% flow. When the thermostat is in the open position the
stub shaft enters the bypass gallery obstructing bypass coolant flow by 50%. This design allows the coolant to reach operating temperature quickly
when cold, while adding extra cooling during normal temperature operation.
