Description - Water Pump Bypass
WARNING: This page is about a different car, the 2005 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.
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. See Fig 1.
| 1 - FROM HEATER |
| 2 - FROM RADIATOR |
| 3 - TO WATER PUMP |
| 4 - ENGINE BYPASS |
| 5 - THERMOSTAT |