Dodge Durango

 Service Manual

Cooling System » Description and operation
Coolant reserve/overflow system

Description

The coolant reserve/overflow tank is integral to the upper fan shroud assembly and is made of high temperature plastic.

Fig. 1 Engine cooling system flow-5.2L/5.9L engines-typical

1 - Heater

2 - BYPASS*

3 - CROSSFLOW RADIATOR

Fig. 2 Engine cooling system flow-4.7L engine-typical

1 - LH CYL. HEAD

2 - BLEED

3 - THERMOSTAT LOCATION

4 - RH CYL. HEAD

5 - RH BANK CYL. BLOCK

6 - LH BANK CYL. BLOCK

7 - COOLANT TEMP. SENSOR

OPERATION

The coolant reserve/overflow system works in conjunction with the radiator pressure cap. It utilizes thermal expansion and contraction of coolant to keep coolant free of trapped air. It provides a volume for expansion and contraction of coolant. It also provides a convenient and safe method for checking coolant level and adjusting level at atmospheric pressure.

This is done without removing the radiator pressure cap. The system also provides some reserve coolant to the radiator to cover minor leaks and evaporation or boiling losses.

As the engine cools, a vacuum is formed in the cooling system of both the radiator and engine. Coolant will then be drawn from the coolant tank and returned to a proper level in the radiator.

Cooling system

Coolant reserve/overflow system

Thermostat-5.2L/5.9L engines

Thermostat-4.7L engine

Radiator pressure cap

Radiator

Water pump

Water pump bypass-4.7L

Water pump bypass hose-5.2L/5.9L engines

Automatic transmission oil coolers

Automatic belt tensioner

Block heater

Hose clamps

Viscous fan drive