Dodge Caliber. Manual - part 169

The cooling system regulates engine operating temperature. It allows the engine to reach normal operating temper-
ature as quickly as possible, maintains normal operating temperature and prevents overheating.

The cooling system also provides a means of heating the passenger compartment. The cooling system is pressur-
ized and uses a centrifugal water pump to circulate coolant throughout the system. Gas engines use a separate and
remotely mounted, ambient pressure coolant recovery bottle using a pressure/vent cap. Diesel engine use a sepa-
rate and remotely mounted, pressurized coolant tank using a pressure/vent cap.

The cooling system consists:

•

Radiator

•

Coolant

•

Electric Cooling Fans

•

Water pump

•

Dual Thermostats (Gas Engines)

1 - WATER PUMP
2 - RETURN TUBE
3 - WATER PLENUM
4 - PRIMARY THERMOSTAT
5 - TRANSMISSION
6 - INTERNAL TRANSMISSION COOLER

7 - COMBINATION COOLER
8 - RADIATOR
9 - SECONDARY THERMOSTAT
10 - CYLINDER BLOCK
11 - CYLINDER HEAD
12 - HEATER CORE

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COOLING

•

Charge air cooler (Turbocharged vehicles only)

•

Hoses and clamps

•

Transmission oil cooler

•

Coolant pressure bottle/overflow system

OPERATION

The primary purpose of a cooling system is to maintain engine temperature in a range that will provide satisfactory
engine performance and emission levels under all expected driving conditions. It also provides hot water (coolant)
for heater performance and cooling for automatic transmission oil. It does this by transferring heat from engine metal
to coolant, moving this heated coolant to the radiator, and then transferring this heat to the ambient air.

•

When the Engine is cold and both the primary and secondary thermostats are closed. The coolant will circulate
through the engine, heater system, which also serves as the bypass, and the internal automatic transmission
oil cooler. 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. 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).

WARNING

COOLING SYSTEM WARNINGS

WARNING: Antifreeze is an ethylene glycol based coolant and is harmful if swallowed or inhaled. If swal-
lowed, drink two glasses of water and induce vomiting. If inhaled, move to fresh air area, seek medical
attention immediately. Do not store in opened or unmarked containers. Wash skin and clothing thoroughly
after coming in contact with ethylene glycol. Keep out of reach of children and pets. Dispose of glycol
based coolant properly, contact your dealer or government agency for location of collection center in your
area. Do not open a cooling system when the engine is at operating temperature or hot under pressure,
personal injury can result. Avoid radiator cooling fan when engine compartment related service is per-
formed, personal injury can result.

DIAGNOSIS AND TESTING

DIAGNOSIS AND TESTING - COOLING SYSTEM AERATION

If coolant level drops below a certain point, aeration will occur drawing air into the water pump resulting in the
following:

•

High reading shown on the temperature gauge.

•

Loss of coolant flow through the heater core.

•

Corrosion in the cooling system.

•

Transmission oil will become hotter (automatic transmission equipped vehicles).

•

Water pump seal may run dry, increasing the risk of premature seal failure.

•

Combustion gas leaks into the coolant can also cause the above problems.

DIAGNOSIS AND TESTING - COOLING SYSTEM DEAERATION

As air is removed from the cooling system, it gathers in the coolant recovery container. This pressure is released
into the atmosphere through the pressure valve located in the radiator pressure cap when pressure reaches 96 -
124 kPa (14 - 18 psi). This air is replaced with coolant from the coolant recovery container.

NOTE: Deaeration does not occur at engine idle, higher engine speeds are required. Normal driving will
deaerate cooling system.

To effectively deaerate the system, multiple thermal cycles of the system may be required.

COOLING

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DIAGNOSIS AND TESTING - COOLING SYSTEM FLOW CHECK

WARNING: Do not remove the cooling system pressure cap with the system hot and under pressure
because serious burns from coolant can occur.

To determine whether coolant is flowing through the cooling system, use one of the following procedures:

•

If engine is cold, idle engine until normal operating temperature is reached. Then feel the upper radiator hose.
If it is hot, coolant is circulating.

•

Remove pressure cap when engine is cold, remove small amount of coolant. Idle engine until thermostat
opens, you should observe coolant flow while looking down the filler neck. Once flow is detected install the
pressure cap.

COOLING SYSTEM LEAK TESTING

WARNING: If vehicle has been run recently, wait 15 minutes before removing pressure cap. Place a shop
towel over the cap, and without pushing down, rotate it counterclockwise to the first stop. Allow fluids to
escape through the overflow tube. When the system stops pushing coolant and steam into the coolant
recovery container and pressure drops, push down on the cap and remove it completely. Squeezing the
radiator inlet hose with a shop towel (to check pressure) before and after turning to the first stop is rec-
ommended.

With engine not running, wipe the coolant filler neck sealing seat clean. The radiator should be full.

Attach Tool 7700 or equivalent cooling system pressure tester to the coolant filler neck. Apply 104 kPa (15 psi)
pressure. If the pressure drops more than 13 kPa (2 psi) in 2 minutes inspect all points for external leaks.

All hoses, radiator and heater, should be moved while at 104 kPa (15 psi) since some leaks occur while driving due
to engine movement, etc.

If there are no external leaks after the gauge dial shows a drop in pressure, detach the tester. Start engine and run
the engine to normal operating temperature in order to open the thermostat and allow the coolant to expand. Reat-
tach the tester. If the needle on the dial fluctuates, it indicates a combustion leak and is usually a head gasket leak.

WARNING: WITH TOOL IN PLACE PRESSURE BUILDS UP FAST. ANY EXCESSIVE AMOUNT OF PRESSURE
BUILT UP BY CONTINUOUS ENGINE OPERATION MUST BE RELEASED TO A SAFE PRESSURE POINT.
NEVER PERMIT PRESSURE TO EXCEED 138 kPa (20 psi).

If the needle on the dial does not fluctuate, race the engine a few times. If an abnormal amount of coolant or steam
is emitted from the tailpipe, it may indicate a damaged head gasket, cracked engine block or cylinder head.

There may be internal leaks which can be determined by removing the oil dipstick. If water globules appear inter-
mixed with the oil, it will indicate an internal leak in the engine. If there is an internal leak, the engine must be
disassembled for repair.

COOLING SYSTEM

CONDITION

POSSIBLE CAUSE

CORRECTION

TEMPERATURE GAUGE READS
LOW

1. Diagnostic Trouble Code (DTC)
has been set indicating a stuck
open engine thermostat.

1. Replace thermostat, if necessary.
If a (DTC) has not been set, the
problem may be with the
temperature gauge.

2. Engine Coolant Temperature
Sensor.

2. Check connector at Engine
Coolant Temperature Sensor. Repair
as necessary.

3. Inoperative temperature gauge.

3. Check gauge operation (Refer to
8 - ELECTRICAL/INSTRUMENT
CLUSTER - DIAGNOSIS AND
TESTING).

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COOLING

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