Principles of Operation: Notes

WARNING: This page is about a different car, the 2013 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

Engine coolant flows primarily from the engine to the radiator circuit and back to the coolant pump. Coolant is sent from the coolant pump through the engine block and cylinder heads. A separate circuit from the engine also feeds the heater core and turbochargers with coolant. The coolant pump, operated by engine rotation through the accessory drive belt, circulates 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 coolant pump. When the thermostat is opened, coolant flows through the radiator circuit to transfer engine-generated heat to the outside air.

The transmission cooler - warmer is mounted on the transmission. On initial startup, the transmission fluid heater coolant control valve opens and allows warm coolant from the engine to enter the transmission cooler - warmer to warm the transmission fluid. As the engine and transmission warm, the transmission fluid heater coolant control valve closes and the transmission fluid cooler coolant control valve opens, allowing cooler coolant from the radiator to enter the transmission cooler - warmer to cool the transmission fluid.

The degas bottle holds surplus coolant and removes air from the cooling system. It also allows for coolant expansion and system pressurization, replenishes coolant to the cooling system and serves as the location for service fill.

The cooling fan draws air through the radiator to help cool the system coolant as it passes through the radiator.

The thermostat monitor is a function of the PCM and is designed to verify correct thermostat operation. The PCM monitors the CHT sensor or ECT sensor (1.6L GTDI) and compares this value to an infered termperature model. The monitor executes once per drive cycle and has a monitor run duration of 300-800 seconds. If a malfunction occurs, DTC P0125 or P0128 sets, and the Malfunction Indicator Lamp (MIL) illuminates.

For engine specific information, refer to SPECIFICATIONS .