Cooling System: Description and Operation

- The engine cooling system consists of a down-flow radiator which features high heat-dissipation performance, an electric motor fan, a water pump, a thermostat, and an engine coolant temperature sensor.
- The reserve tank is designed to eliminate the need for replenishing coolant.
- On models without an air conditioner, the ECM sends an ON or OFF switch signal to the radiator fan in response to signals from the engine coolant temperature sensor. On models with an air conditioner, the ECM sends ON or OFF switch signals to the radiator main fan and sub fan in response to signals from the engine coolant temperature sensor, vehicle speed sensor 2 and A/C switch.

Cooling Lines





This cooling system operates in three steps depending on the temperature of the engine coolant flowing through the cooling circuit.
- 1st step With thermostat closed
At the engine coolant temperature of below 76°C (169°F) , the thermostat remains closed and the engine coolant flows through the bypass and heater circuits.
This permits the engine to warm up quickly.
- 2nd step With thermostat opened
When the engine coolant temperature is above 76 - 80°C (169 - 176°F) , the thermostat opens and the engine coolant flows through the radiator where it is cooled.
- 3rd step With radiator fan operating
When the engine coolant temperature rises above 95°C (203°F) , the ECM sends ON signal to the radiator fan in response to signal from the engine coolant temperature sensor and the radiator fan.

Water Pump





The water pump is located on the left front portion of the cylinder block and is driven by the timing belt. The thermostat is built into the engine coolant inlet located on the lower side of the water pump. When the impeller rotates, engine coolant is drawing into the water pump from the lower pipe (which is connected to the radiator hose) via the thermostat. It then flows along the perimeter of the impeller and is delivered to the engine's engine coolant passage.

Mechanical Seal





The mechanical seal has its seat pressed into the water pump shaft to form the seal and water pump as a single unit. With this design, the water pump cannot be disassembled.

Thermostat





The thermostat is powered to open the valve by a totally - enclosed wax pellet which expands with increased temperature. It provides the sure open - close operation of the valve and features high durability.

Radiator Fan





- The radiator fan is made of plastic. That is installed to the electric motor, and is located onto radiator straight by shroud.
- The vehicle without air conditioning has the radiator main fan only. Thus, the vehicle with air conditioning has the radiator sub fan, too.

Radiator Fan Control

WITHOUT A/C MODELS





The ON-OFF control of the radiator fan is governed by the ECM which receives signals sent from the engine coolant temperature sensor.

WITH A/C MODEL





On models which are equipped with an air conditioning system, the ECM receives signals sent from the engine coolant temperature sensor, vehicle speed sensor 2 and A/C switch. These signals simultaneously turn ON or OFF the radiator main fan and radiator sub fan.