Engine Cooling System: Overview Dodge Avenger II facelift

Scheme 1

The cooling system consists of an engine cooling module, thermostat, non-pressure coolant recovery container or pressurized coolant recovery container (3.6L), coolant, hoses, and a water pump to circulate the coolant. The engine cooling module consists of a radiator, electric fans, shroud, transmission oil cooler, and air conditioning condenser.

Scheme 2

DESCRIPTION

Correct drive belt tension is required to ensure optimum performance of the belt driven engine accessories. If specified tension is not maintained, belt slippage may cause; engine overheating, lack of power steering assist, loss of air conditioning capacity, reduced generator output rate, and greatly reduced belt life.

It is not necessary to adjust belt tension. All engines are equipped with an automatic belt tensioner. The tensioner maintains correct accessory drive belt tension at all times.

Scheme 3

1. Raise vehicle on hoist.
2. Remove belt splash shield.
3. Remove accessory drive belt. Refer to «BELT, SERPENTINE, REMOVAL»(ref-485484-S39989615472012071300000) .
4. Remove accessory drive belt tensioner mounting bolt. Remove accessory drive belt tensioner (8).

OPERATION

The radiator fans are controlled by the Powertrain Control Module (PCM) which energizes a high speed or low speed fan relay. The electric motor drives the cooling fan to produce air flow across the radiator fins.

The sensor is located at the top of the coolant adapter housing. The ECT Sensor is a negative thermal coefficient sensor.

The ECT sensor provides an input to the PCM. As temperature increases, resistance of the sensor decreases. As coolant temperature varies, the ECT sensor resistance changes resulting in a different voltage value at the PCM ECT sensor signal circuit. The ECT sensor provides input for various PCM operations. The PCM uses the input to control air-fuel mixture, timing, and radiator fan on/off times. The PCM uses ECT sensor input to send messages over the CAN bus to various modules for other functions such as temperature gauge and AC operation.

Scheme 4

1. Disconnect negative battery cable.
2. Partially drain cooling system below level of ECT Sensor (1).
3. Disconnect ECT Sensor electrical connector.
4. Remove ECT Sensor (1) by pressing the locking tab and twisting the sensor counter clockwise.

Scheme 5

The Engine Coolant Temperature (ECT) sensor on the 3.6L engine is installed into a water jacket at rear of the cylinder head on the left side of the engine.

Note. Do not waste reusable coolant. If solution is clean, drain coolant into a clean container for reuse.

1. Partially drain the cooling system. Refer to «STANDARD PROCEDURE»(ref-485484-S02211614932012071300000) .
2. Disconnect the electrical connector from the sensor.
3. Remove the sensor from the cylinder head.

Scheme 6

1. Install ECT Sensor (1). Make sure coolant sensor is locked in place
2. Reconnect ECT Sensor electrical connector.
3. Fill cooling system. Refer to «STANDARD PROCEDURE»(ref-485484-S02211614932012071300000) .
4. Connect negative battery cable.

When the engine is cold and both the primary and secondary thermostats are closed. The coolant will circulate through the engine, heater system, and the bypass. The cooling system has no flow through the radiator

As the engine warms up, the primary thermostat will start to open at 82 °C (179 °F). Coolant will start to flow through the radiator oil cooler and transmission cooler. Coolant will flow through the transmission oil cooler only when the primary thermostat is fully open. The primary thermostat will fully open at 95 °C (203 °F).

The secondary thermostat will start to open at 95 °C (203 °F). This will increase the coolant flow through the cylinder block and cylinder head and the radiator. The secondary thermostat will fully open at 110 °C (230 °F).

If the thermostat is stuck open or allows coolant leakage through it, the engine will not operate at the proper temperature for obtaining engine fuel efficiency, performance and emissions levels. If this condition occurs, a diagnostic trouble code will be set and a MIL light will be turned on. Refer to POWERTRAIN CONTROL MODULE (PCM) - ELECTRICAL DIAGNOSTICS - 40TE AUTOMATIC TRANSMISSION or POWERTRAIN CONTROL MODULE (PCM) - ELECTRICAL DIAGNOSTICS - 62TE AUTOMATIC TRANSMISSION for further information and diagnostics provided.

An external oil-to-air type automatic transmission oil cooler is mounted to the front of the radiator and is integral to the A/C condenser. The six upper tubes are used for transaxle oil cooling, and the remaining tubes below are for the A/C system.

The cooler uses tubes and rubber hoses to feed oil to and from the automatic transaxle. The replaceable inlet and outlet tubes use quick-connect type fittings. The trans oil cooler is replaced with the A/C condenser.

Scheme 7

The transmission oil flows from the transmission to the oil-to-air cooler. Heat is then transferred into the air. The transmission oil cooler is integral to the A/C condenser and can only be serviced as an assembly. Refer to CONDENSER, A/C, REMOVAL .