Normal Operation

The engine cooling system functions to maintain engine temperatures during operation. Correct coolant flow through the engine, radiator and remainder of cooling system passages and components is essential to maintaining a correct engine temperature.

Engine coolant flows primarily from the engine to the radiator circuit and back to the water pump. From the water pump, coolant is sent through the engine block and cylinder heads. A separate circuit from the engine also feeds the heater core with coolant. The water pump is operated by engine rotation through a pulley which is driven by a drive belt to circulate the coolant. The coolant thermostat is a control valve actuated by coolant temperature. When the thermostat is closed, coolant flow bypasses the radiator circuit and returns to the water pump. When the thermostat is opened, coolant is allowed to flow through the radiator circuit in order to transfer engine generated heat to the outside air.

Engine overheating generally occurs when there is a disruption in the ability to control either coolant flow at the correct rate, the inability to transfer heat from the engine through the coolant (including low coolant), or an inability to transfer engine generated heat to the outside air through the radiator.

For vehicle/engine specific information, see ENGINE COOLING DESCRIPTION AND OPERATION - 2.5L or ENGINE COOLING DESCRIPTION/OPERATION - 3.0L .

• DTC P0217 Engine Coolant Over Temperature Condition
• DTC P1285 Cylinder Head Over Temperature Condition
• DTC P1299 Cylinder Head Over Temperature Protection Active