Chrysler RAM TRUCK 2500 1994 Service Manual page 300

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COOLING SYSTEM 7 - 45
CAUTION: SI f a n blade assembly is replaced be­
c a u s e of mechanical d a m a g e , w a t e r p u m p a n d v i s ­
c o u s f a n d r i v e s h o u l d a l s o b e i n s p e c t e d . T h e s e
c o m p o n e n t s c o u l d h a v e b e e n d a m a g e d d u e to ex­
c e s s i v e v i b r a t i o n .
INSTALLATION
(1) Install fan blade assembly to viscous fan drive.
Tighten bolts (Fig. 69) to 23 N-m (17 ft. lbs.) torque.
(2) Position fan shroud and fan blade/viscous fan
drive assembly to vehicle as a complete unit.
(3) Install fan shroud.
(4) Install fan blade/viscous fan drive assembly to
water pump shaft (Fig. 69).
(5) Except 8.0L V-10 Engine: Install coolant re­
serve/overflow tank to fan shroud. Snaps into posi­
tion.
(6) Install throttle cable to fan shroud.
(7) Connect negative battery cable.
COOLING SYSTEM FAN—DIESEL ENGINE
REMOVAL
(1) Disconnect negative battery cable from battery.
(2) Remove the fan shroud mounting bolts. Posi­
tion fan shroud towards engine.
CAUTION: Do not remove the fan pulley bolts. This
pulley is under spring tension.
(3) The thermal viscous fan drive/fan blade assem­
bly is attached (threaded) to the fan hub shaft (Fig.
70). Remove the fan blade/fan drive assembly from
fan pulley by turning the mounting nut clockwise (as
viewed from front). Threads on the viscous fan drive
are L E F T H A N D . A Snap-On 36 M M Fan Wrench
(number SP346 from Snap-On Cummins Diesel Tool
Set number 2017DSP) can be used. Place a bar or
screwdriver between the fan pulley bolts to prevent
pulley from rotating.
(4) Remove the fan shroud and the fan blade/vis­
cous drive as an assembly from vehicle.
(5) Remove fan blade-to-viscous fan drive mount­
ing bolts.
Inspect the fan for cracks, loose rivets, loose or
bent fan blades.
INSPECTION
The fan cannot be repaired. I f the fan is damaged,
it must be replaced. Inspect the fan as follows:
(1) Remove fan blade and thermal viscous fan
drive assembly from engine. Refer to the preceding
Removal procedure.
(2) Remove fan blade assembly from thermal vis­
cous fan drive unit (four bolts).
(3) Lay fan on a flat surface with leading edge fac­
ing down. With tip of blade touching flat surface, re-
THREADED
Fig. 70 Fan Blades/Viscous Fan Drive—5.9L Diesel
place fan i f clearance between opposite blade and
surface is greater than 2.0 mm (.090 inch). Rocking
motion of opposite blades should not exceed 2.0 mm
(.090 inch). Test all blades i n this manner.
WARNING: DO NOT ATTEMPT TO BEND OR
STRAIGHTEN FAN B L A D E S IF NOT WITHIN S P E C I ­
FICATIONS.
(4) Inspect fan assembly for cracks, bends, loose
rivets or broken welds. Replace fan i f any damage is
found.
CAUTION: If the fan blade assembly is replaced be­
c a u s e of mechanical damage, the fan pulley and
v i s c o u s fan drive should also be inspected. T h e s e
components could have been damaged due to ex­
c e s s i v e vibration.
INSTALLATION
(1) Install fan blade assembly to viscous fan drive.
Tighten mounting bolts to 23 N-m (17 ft. lbs.) torque.
(2) Position the fan shroud and fan blade/viscous
fan drive to the vehicle as an assembly.
(3) Install viscous fan drive assembly on fan hub
shaft. Tighten mounting nut to 57 N-m (42 ft. lbs.)
torque.
(4) Install fan shroud bolts.
(5) Install battery cable to battery.
VISCOUS FAN DRIVE
The thermal viscous fan drive (Figs. 69 or 70) con­
sists of the viscous fan drive clutch and a thermo­
static spring coil mounted on its front face (Fig. 71).