Chrysler RAM TRUCK 2500 1994 Service Manual page 292

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COOLING SYSTEM 7 - 37
R E V E R S E FLUSHING ENGINE—EMCEPT
DIESEL
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 wa­
ter pump inlet fitting.
CAUTION: O n v e h i c l e s e q u i p p e d w i t h a heater water
c o n t r o l v a l v e , he s u r e heater c o n t r o l valve is c l o s e d
(heat off). T h i s w i l l prevent c o o l a n t f l o w w i t h scale
a n d other d e p o s i t s f r o m entering heater c o r e .
Connect water supply hose and air supply hose to
flushing gun. Allow engine to fill with water. When
engine is filled, apply air i n 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 supply
hose and air supply hose. Remove thermostat hous­
ing and install thermostat. Install thermostat hous­
ing with a replacement gasket. Refer to Thermostat
Replacement. Connect radiator hoses. Refill cooling
system with correct antifreeze/water mixture. Refer
to Refilling the Cooling System.
R E V E R S E 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.
CAUTION: Be s u r e t h e heater c o n t r o l valve is
c l o s e d (heat off). T h i s w i l l prevent c o o l a n t f l o w w i t h
scale a n d other d e p o s i t s f r o m entering the heater
core.
(4) Remove the heater core inlet hose from tube
(Fig. 56).
(5) Attach water supply hose to heater tube.
(6) Back-flush the engine until clean water exits
the water pump inlet.
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 i n s t r u c t i o n s w h e n
u s i n g t h e s e p r o d u c t s .
TESTING COOLING SYSTEM FOR LEAKS
U L T R A V I O L E T L I G H T
METHOD
A leak detection additive is available through the
parts department that can be added to cooling sys­
tem. The additive is highly visible under ultraviolet
light (black light). Pour one ounce of additive into
cooling system. Place heater control unit i n HEAT
position. Start and operate engine until radiator up­
per hose is warm to touch. A i m black light (tool
C-4555 or an equivalent) at components to be
checked. I f leaks are present, black light will cause
additive to glow a bright green color.
The black light can be used i n conjunction with a
pressure tester to determine i f any external leaks ex­
ist (Fig. 57).
Fig. 57 Leak Detection Using Black Light—Typical
Fig. 56 Typical Reverse-flushing—5.9L Diesel