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Dodge Ram Truck 1500-2500-3500. Manual - part 228

CONDITION

POSSIBLE CAUSES

CORRECTION

INADEQUATE HEATER
PERFORMANCE. THERMOSTAT
FAILED IN OPEN POSITION

1. Has a Diagnostic trouble Code
(DTC) been set?

1. (Refer to 25 - EMISSIONS
CONTROL - DESCRIPTION) for
correct procedures and replace
thermostat if necessary

2. Coolant level low

2. (Refer to 7 - COOLING -
DIAGNOSIS AND TESTING).

3. Obstructions in heater hose/
fittings

3. Remove heater hoses at both
ends and check for obstructions

4. Heater hose kinked

4. Locate kinked area and repair as
necessary

5. Water pump is not pumping
water to/through the heater core.
When the engine is fully warmed
up, both heater hoses should be
hot to the touch. If only one of the
hoses is hot, the water pump may
not be operating correctly or the
heater core may be plugged.
Accessory drive belt may be
slipping causing poor water pump
operation.

5. (Refer to 7 - COOLING/ENGINE/
WATER PUMP - REMOVAL). If a
slipping belt is detected, (Refer to 7
- COOLING/ACCESSORY
DRIVE/DRIVE BELTS - DIAGNOSIS
AND TESTING). If heater core
obstruction is detected, (Refer to 24
- HEATING & AIR
CONDITIONING/PLUMBING/
HEATER CORE - REMOVAL).

STEAM IS COMING FROM THE
FRONT OF VEHICLE NEAR THE
GRILL AREA WHEN WEATHER IS
WET, ENGINE IS WARMED UP
AND RUNNING, AND VEHICLE IS
STATIONARY. TEMPERATURE
GAUGE IS IN NORMAL RANGE

1. During wet weather, moisture
(snow, ice or rain condensation) on
the radiator will evaporate when the
thermostat opens. This opening
allows heated water into the
radiator. When the moisture
contacts the hot radiator, steam
may be emitted. This usually occurs
in cold weather with no fan or air
flow to blow it away.

1. Occasional steam emitting from
this area is normal. No repair is
necessary.

COOLANT COLOR

1. Coolant color is not necessarily
an indication of adequate corrosion
or temperature protection. Do not
rely on coolant color for determining
condition of coolant.

1. (Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES -
DESCRIPTION) Adjust coolant
mixture as necessary.

COOLANT LEVEL CHANGES IN
COOLANT RESERVE/OVERFLOW
TANK. TEMPERATURE GAUGE IS
IN NORMAL RANGE

1. Level changes are to be
expected as coolant volume
fluctuates with engine temperature.
If the level in the tank was between
the FULL and ADD marks at normal
operating temperature, the level
should return to within that range
after operation at elevated
temperatures.

1. A normal condition. No repair is
necessary.

7 - 18

COOLING

DR/DH

STANDARD PROCEDURE

COOLANT LEVEL CHECK

NOTE: Do not remove radiator cap for routine coolant level inspections. The coolant level can be checked
at coolant recovery bottle or the coolant degas bottle.

WARNING: DO NOT REMOVE OR LOOSEN THE RADIATOR CAP WITH THE COOLING SYSTEM HOT AND
UNDER PRESSURE. SERIOUS BURNS FROM COOLANT OR HIGH PRESSURE STEAM CAN OCCUR.

The coolant reserve/overflow system provides a quick method for determining the coolant level without removing the
radiator pressure cap. With the engine at normal operating temperature and idling, observe the level of the coolant
on the external level indicator on the side of the coolant reserve / overflow bottle. The coolant level should be
between the MIN and MAX marks. If the coolant is below the MIN mark, add coolant (Refer to LUBRICATION &
MAINTENANCE/FLUID TYPES - DESCRIPTION) to the bottle until the level reaches the MIN mark. Do Not Overfill
the bottle by adding fluid above the MAX line. This may cause coolant to spill onto the ground during subse-
quent vehicle operation.

COOLING SYSTEM CLEANING/REVERSE FLUSHING

CLEANING

Drain the cooling system and refill with water. Run the engine with the radiator cap installed until the upper radiator
hose is hot. Stop the engine and drain the water from system. If the water is dirty, fill the system with water, run the
engine and drain the system. Repeat this procedure until the water drains clean.

REVERSE FLUSHING

Reverse flushing of the cooling system is the forcing of water through the cooling system. This is done using air
pressure in the opposite direction of normal coolant flow. It is usually only necessary with very dirty systems with
evidence of partial plugging.

REVERSE FLUSHING RADIATOR

Disconnect the radiator hoses from the radiator inlet and outlet. Attach a section of the radiator hose to the radiator
bottom outlet fitting and insert the flushing gun. Connect a water supply hose and air supply hose to the flushing
gun.

CAUTION: Internal radiator pressure must not exceed 138 kPa (20 psi) as damage to radiator may result.

Allow the radiator to fill with water. When the radiator is filled, apply air in short blasts. Allow the radiator to refill
between blasts. Continue this reverse flushing until clean water flows out through the rear of the radiator cooling
tube passages.

REVERSE FLUSHING ENGINE

Drain the cooling system. Remove the thermostat housing and thermostat. Install the thermostat housing. Discon-
nect the radiator upper hose from the radiator and attach the flushing gun to the hose. Disconnect the radiator lower
hose from the water pump and attach a lead-away hose to the water pump inlet fitting.

CAUTION: On vehicles equipped with a heater water control valve, be sure the heater control valve is
closed (heat off). This will prevent coolant flow with scale and other deposits from entering the heater core.

Connect the water supply hose and air supply hose to flushing gun. Allow the engine to fill with water. When the
engine is filled, apply air in short blasts, allowing the system to fill between air blasts. Continue until clean water
flows through the lead away hose.

Remove the lead away hose, flushing gun, water supply hose and air supply hose. Remove the thermostat housing
and install the thermostat. Install the thermostat housing with a replacement gasket. Refer to Thermostat Replace-
ment. Connect the radiator hoses. Refill the cooling system with the correct antifreeze/water mixture (Refer to
LUBRICATION & MAINTENANCE/FLUID TYPES - DESCRIPTION). Refer to Refilling the Cooling System.

DR/DH

COOLING

7 - 19

CHEMICAL CLEANING

In some instances, use a radiator cleaner (Mopar

Radiator Kleen or equivalent) before flushing. This will soften

scale and other deposits and aid flushing operation.

CAUTION: Follow manufacturers instructions when using these products.

DRAINING COOLING SYSTEM - ALL GAS ENGINES

WARNING: DO NOT REMOVE CYLINDER BLOCK
DRAIN PLUGS OR LOOSEN RADIATOR DRAIN-
COCK WITH SYSTEM HOT AND UNDER PRES-
SURE. SERIOUS BURNS FROM COOLANT CAN
OCCUR.

DO NOT WASTE reusable coolant. If solution is clean,
drain coolant into a clean container for reuse.

1. Attach one end of a hose to the draincock. Put the

other end into a clean container.

2. DO NOT REMOVE THE RADIATOR CAP when

draining the coolant from the reservoir/overflow
tank. Open radiator draincock and when the tank is
empty, remove the radiator cap and continue drain-
ing the cooling system.

3. If draining the entire engine, remove the cylinder

block drain plugs. Refer to or.

REFILLING COOLING SYSTEM - ALL GAS ENGINES

WARNING: DO NOT REMOVE CYLINDER BLOCK DRAIN PLUGS OR LOOSEN RADIATOR DRAINCOCK WITH
SYSTEM HOT AND UNDER PRESSURE. SERIOUS BURNS FROM COOLANT CAN OCCUR.

7 - 20

COOLING

DR/DH

DO NOT WASTE reusable coolant. If solution is clean, drain coolant into a clean container for reuse.

Clean cooling system prior to refilling. (Refer to 7 - COOLING - STANDARD PROCEDURE).

1. Install cylinder block drain plugs. Coat the threads with Mopar

Thread Sealant with Teflon.

2. Close radiator petcock.

3. Fill cooling system with the antifreeze mixture (Refer to LUBRICATION & MAINTENANCE/FLUID TYPES -

DESCRIPTION).

4. Fill coolant reserve/overflow tank to MAX mark on bottle.

5. Start and operate engine until thermostat opens (upper radiator hose warm to touch).

6. If necessary, add antifreeze mixture to the coolant reserve/overflow tank. This is done to maintain coolant level

between the MAX and MIN marks. The level in the reserve/overflow tank may drop below the MIN mark after
three or four warm-up and cool-down cycles.

DRAINING COOLING SYSTEM - 5.9L DIESEL ENGINE

WARNING: DO NOT REMOVE THE CYLINDER BLOCK DRAIN PLUGS OR LOOSEN THE RADIATOR DRAIN
PLUG WITH SYSTEM HOT AND UNDER PRESSURE. SERIOUS BURNS FROM COOLANT CAN OCCUR.

DO NOT WASTE reusable coolant. If the solution is clean, drain the coolant into a clean container for reuse.

1. Start the engine and place the heater control temperature selector in the Full-On position.

2. Turn the ignition off.

3. Do not remove radiator cap when draining coolant from reserve/overflow tank. Open radiator drain plug and

when tank is empty, remove radiator cap. If the coolant reserve/overflow tank does not drain, (Refer to 7 -
COOLING - DIAGNOSIS AND TESTING). The coolant need not be removed from tank unless the system is
being refilled with fresh mixture.

4. Remove radiator pressure cap.

REFILLING COOLING SYSTEM - 5.9L DIESEL ENGINE

Clean cooling system prior to refilling (Refer to 7 - COOLING - STANDARD PROCEDURE).

1. Close radiator drain plug.

CAUTION: Due to the use of the one-way check valve, the engine must not be operating when refilling the
cooling system.

NOTE: The diesel engine is equipped with two one-way check valves (jiggle pins). The check valves are
used as a servicing feature and will vent air when the system is being filled. Water pressure (or flow) will
hold the valves closed.

2. Fill the cooling system with a 50/50 mixture of water and antifreeze.

3. Fill coolant reserve/overflow tank to the FULL mark.

4. Start and operate engine until thermostat opens. Upper radiator hose should be warm to touch.

5. If necessary, add 50/50 water and antifreeze mixture to the coolant reserve/overflow tank to maintain coolant

level. This level should be between the ADD and FULL marks. The level in the reserve/overflow tank may drop
below the ADD mark after three or four warm-up and cool-down cycles.

ADDING ADDITIONAL COOLANT

The use of aluminum cylinder blocks, cylinder heads and water pumps requires special corrosion protection. In
order to maintain the required protection for these components and cooling system performance, only use the
appropriate fluid (Refer to LUBRICATION & MAINTENANCE/FLUID TYPES - DESCRIPTION) when servicing the
vehicle. This coolant offers the best engine cooling without corrosion when mixed with 50% distilled water to obtain
a freeze point of -37°C (-35°F). If it loses color or becomes contaminated, drain, flush, and replace with fresh prop-
erly mixed coolant solution. This coolant offers the best engine cooling without corrosion when mixed with 50%
distilled water to obtain a freeze point of -37°C (-35°F). If it loses color or becomes contaminated, drain, flush, and
replace with fresh properly mixed coolant solution.

DR/DH

COOLING

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