Chrysler Concorde 2004 Service Manual page 1553

LH
COOLING (Continued)
Fig. 2 PRESSURE TESTING COOLING SYSTEM
perature in order to open the thermostat and allow
the coolant to expand. Reattach the tester. If the nee-
dle on the dial fluctuates it indicates a combustion
leak, 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 tail pipe, it may
indicate a faulty head gasket, cracked engine block or
cylinder head.
There may be internal leaks which can be deter-
mined by removing the oil dipstick. If water globules
appear intermixed 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.
DIAGNOSIS AND TESTING - COOLING SYSTEM
AERATION
Low coolant level in a cross flow radiator will
equalize in both tanks with engine off. With engine
at running and at operating temperature, the high
pressure inlet tank runs full and the low pressure
outlet tank drops. If this level drops below the top of
the transmission oil cooler, aeration will occur draw-
ing air into the water pump resulting in the follow-
ing:
• 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.
• 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 gath-
ers in the coolant bottle. This pressure is released
into the atmosphere through the pressure valve
located in the pressure cap when pressure reaches 96
- 124 kPa (14 - 18 psi). This air is replaced with cool-
ant from the coolant bottle, when the system is
allowed to cool.
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 ther-
mal cycles of the system may be required.
STANDARD PROCEDURE
STANDARD PROCEDURE - COOLANT LEVEL
CHECK
NOTE: Do not remove coolant bottle pressure cap
for routine coolant level inspections.
The coolant bottle provides a quick visual method
for determining the coolant level without removing
the pressure cap. With the engine cold, the level of
the coolant in the coolant bottle (Fig. 3) should be
between the MIN and MAX lines on the bottle.
Fig. 3 COOLANT BOTTLE COLD FILL LEVEL
1 - COOLANT PRESSURE BOTTLE
COOLING 7 - 7