Grand Cherokee 2WD V8-4.7L VIN J (2004)
Water Pump: Description and Operation
Water Pump Bypass
DESCRIPTION-WATER PUMP BYPASS
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 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.
