Description And Operation
The cooling system regulates engine operating temperature. It allows the engine to reach normal operating temperature as quickly as possible, maintains normal operating temperature and prevents overheating.
The cooling system also provides a means of heating the passenger compartment and cooling the engine oil. The cooling system is pressurized and uses a centrifugal water pump to circulate coolant throughout the system. A separate and remotely mounted, pressurized coolant bottle is used.
- When the engine is cold the thermostat is closed. The cooling system has no flow through the radiator or engine oil cooler. The coolant flows through the engine, water pump, and passenger compartment heater core.
- When the engine is warm the thermostat is full open. Coolant flows through the engine, radiator, engine oil cooler, passenger compartment heater core, and water pump.
The cooling system consists of:
- Electric cooling fan
- Radiator
- A pressurized coolant de-aeration bottle
- Thermostat
- Water pump
- Engine Coolant Temperature (ECT) sensor
- Cooling system pressure cap
- Coolant
- Engine oil cooler
- Hoses and hose clamps
- Thermostat housing assembly
The electric cooling fan is controlled by the Powertrain Control Module (PCM). The single speed electric cooling fan is powered through a fuse and high speed relay (a second, low speed relay is not used to control any components and has no external function) and are located in the underhood Power Distribution Center (PDC). The PCM receives input signals from various sensors and switches including the Engine Coolant Temperature (ECT) sensor, A/C system pressure, transmission oil temperature and are used to determine when to actuate the cooling fan. The PCM sends a ground signal to the cooling fan relay. The electric cooling fan is integral to the fan shroud and is located between the radiator and the engine and is not serviceable separately. Any failure of the fan blade, electric motor or fan shroud requires replacement of the fan module.