RAM 1500 Truck 2WD V6-3.7L VIN K (2003)
Water Pump: Description and Operation
Water Pump Bypass
WATER PUMP BYPASS
DESCRIPTION
The 3.7L and 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
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.
