Cooling System Cleaning/Reverse Flushing; Refilling Cooling System - Dodge ram truck 3500 1996 Service Manual

7 - 34 COOLING SYSTEM -
S E R V I C E P R O C E D U R E S (Continued)
REFILLING COOLING SYSTEM
Clean cooling system prior to refilling. Refer to
Cooling System Cleaning section of this group.
(1) Install the cylinder block drain plugs (Fig. 36).
(2) Close radiator drain plug.
(3) Fill the cooling system with a 50/50 mixture of
water and antifreeze. 5.9L Diesel Engine Only; The
diesel engine is equipped with a one-way check valve
(jiggle pin). The check valve is used as a servicing
feature and will vent air when the system is being
filled. Water pressure (or flow) will hold the valve
closed. Due to the use of this valve, the engine
must not be operating when r e f i l l i n g the cool­
ing system. Refer to Thermostat Operation—5.9L
Diesel Engine in the Thermostat section of this group
for more information.
(4) Fill coolant reserve/overflow tank to the FULL
mark.
(5) Start and operate engine until thermostat
opens. Upper radiator hose should be warm to touch.
(6) I f necessary, add 50/50 water and antifreeze
mixture to the coolant reserve/overflow tank to main­
tain coolant level. This level should be between the
ADD and FULL marks. The level in the reserve/over­
flow tank may drop below the ADD mark after three
or four warm-up and cool-down cycles.
COOLING SYSTEM CLEANING/REVERSE FLUSHING
CLEANING
Drain cooling system and refill with water. Run
engine with radiator cap installed until upper radia­
tor hose is hot. Stop engine and drain water from
system. I f water is dirty, fill system with water, run
engine and drain system. Repeat until water drains
clean.
REVERSE
FLUSHING
Reverse flushing of cooling system is the forcing of
water through the cooling system. This is done using
air pressure in the opposite direction of normal cool­
ant flow. I t is usually only necessary with very dirty
systems with evidence of partial plugging.
REVERSE FLUSHING RADIATOR
Disconnect radiator hoses from radiator inlet and
outlet. Attach a section of radiator hose to radiator
bottom outlet fitting and insert flushing gun. Con­
nect a water supply hose and air supply hose to
flushing gun.
CAUTION: Internal radiator pressure must not
exceed 138 kPa (20 psi) as damage to radiator may
result.
Allow radiator to fill with water. When radiator is
filled, apply air in short blasts. Allow radiator to
refill between blasts. Continue this reverse flushing
until clean water flows out through rear of radiator
cooling tube passages. Have radiator cleaned more
extensively by a radiator repair shop.
REVERSE FLUSHING ENGINE-VS V-8
S
AND
V-10
Drain cooling system. Remove thermostat housing
and thermostat. Install thermostat housing. Discon­
nect radiator upper hose from radiator and attach
flushing gun to hose. Disconnect radiator lower hose
from water pump and attach a lead-away hose to
water pump inlet fitting.
Connect water supply hose and air supply hose to
flushing gun. Allow engine to fill with water. When
engine is filled, apply air in short blasts, allowing
system to fill between air blasts. Continue until clean
water flows through the lead away hose.
Remove lead away hose, flushing gun, water sup­
ply hose and air supply hose. Remove thermostat
housing and install thermostat. Install thermostat
housing with a replacement gasket. Refer to Thermo­
stat Replacement. Connect radiator hoses. Refill cool­
ing system with correct antifreeze/water mixture.
Refer to Refilling the Cooling System.
REVERSE FLUSHING ENGINE—DIESEL
(1) Drain the cooling system.
(2) Disconnect the upper hose from the radiator.
(3) Disconnect the radiator lower hose from the
water pump.
(4) Remove the heater core inlet hose from tube
(Fig. 37).
Fig. 37 Typical Reverse-flushing—5.9L Diesel
(5) Attach water supply hose to heater tube.
(6) Back-flush the engine until clean water exits
the water pump inlet.