Thermostat—5.2L/5.9L Engines - Dodge 2000 DURANGO Service Manual

DN
DESCRIPTION AND OPERATION (Continued)
1 – LH CYL. HEAD
2 – BLEED
3 – THERMOSTAT LOCATION
4 – RH CYL. HEAD
OPERATION
The coolant reserve/overflow system works in con-
junction 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. Cool-
ant will then be drawn from the coolant tank and
returned to a proper level in the radiator.
Fig. 2 Engine Cooling System Flow—4.7L Engine—Typical
5 – RH BANK CYL. BLOCK
6 – LH BANK CYL. BLOCK
7 – COOLANT TEMP. SENSOR
THERMOSTAT—5.2L/5.9L ENGINES
DESCRIPTION
CAUTION: Do not operate an engine without a ther-
mostat, except for servicing or testing.
The thermostat on all gas powered engines is
located beneath the thermostat housing at the front
of the intake manifold (Fig. 4).
The thermostat is a wax pellet driven, reverse pop-
pet choke type.
Coolant leakage into the pellet container will cause
the thermostat to fail in the open position. Thermo-
stats very rarely stick. Do not attempt to free a ther-
mostat with a prying device.
COOLING SYSTEM 7 - 3