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7 - 4
COOLING
COOLING (Continued)
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, resulting in cooling system aera-
tion. Aeration will draw 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.
• 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
Air can only be removed from the system by gath-
ering under the pressure cap. On the next heat up it
will be pushed past the pressure cap into the coolant
recovery bottle by thermal expansion of the coolant.
It then escapes to the atmosphere in the coolant
recovery bottle and is replaced with coolant on cool
down.
To effectively deaerate the system, multiple ther-
mal cycles of the system may be required.
NOTE: Deaeration does not occur at engine idle—
higher engine speeds are required. Normal driving
will deaerate cooling system.
STANDARD PROCEDURE
STANDARD PROCEDURE - COOLING SYSTEM
DRAINING
WARNING: DO NOT REMOVE OR LOOSEN THE
COOLANT PRESSURE CAP, CYLINDER BLOCK
DRAIN PLUGS, OR THE DRAINCOCK WHEN THE
SYSTEM
IS
HOT
BECAUSE SERIOUS BURNS FROM THE COOLANT
CAN OCCUR.
(1) Without removing radiator pressure cap
and with system not under pressure, open the
draincock. The draincock is located on the lower left
side of radiator (Fig. 5).
(2) After the coolant recovery/reserve container is
empty, then remove coolant pressure cap (Fig. 6).
(3) Remove the cylinder block drain plug(s).
AND
UNDER
PRESSURE
Fig. 5 Draincock Location
1 - LEFT SIDE FRAME RAIL
2 - DRAINCOCK
STANDARD PROCEDURE - COOLING SYSTEM
FILLING
Remove radiator pressure cap (Fig. 6) and fill sys-
tem, using a 50/50 mix of Mopar Antifreeze/Coolant,
5 Year/100,000 Mile Formula and distilled water.
Continue filling system until full. Be careful not
to spill coolant on drive belts or the generator.
Fill coolant recovery/reserve container (Fig. 6) to at
least the MAX mark with 50/50 solution. It may be
necessary to add coolant to the recovery/reserve con-
tainer after three or four warm up/cool down cycles
to maintain coolant level between the MAX and MIN
mark. This will allow trapped air to be removed from
the system.
STANDARD PROCEDURE - ADDING
ADDITIONAL COOLANT
The radiator cap should not be removed.
When additional coolant is needed to maintain this
level, it should be added to the coolant recovery/re-
serve container (Fig. 6). Use only 50/50 mix of ethyl-
ene glycol type antifreeze and distilled water. For the
recommeded antifreeze/coolant type (Refer to LUBRI-
CATION
&
MAINTENANCE/FLUID
DESCRIPTION).
CAUTION: Do not use well water, or suspect water
supply in cooling system. A 50/50 ethylene glycol
and distilled water mix is recommended. For the
recommeded
antifreeze/coolant
LUBRICATION & MAINTENANCE/FLUID TYPES -
DESCRIPTION).
RS
TYPES
-
type
(Refer
to
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