set clock DODGE RAM 2001 Service User Guide

CAUTION: A number or letter is stamped into the
tongue of constant tension clamps. If replacement
is necessary, use only an original equipment clamp
with a matching number or letter.
(5) Remove radiator upper hose at radiator.
(6) The thermal viscous fan drive is attached
(threaded) to the water pump hub shaft (Fig. 55).
Remove the fan/fan drive assembly from water pump
by turning the mounting nut counterclockwise (as
viewed from front). Threads on the fan drive are
RIGHT-HAND.A Snap-On 36 MM Fan Wrench
(number SP346 from Snap-On Cummins Diesel Tool
Set number 2017DSP) can be used with Special Tool
6958 Spanner Wrench and Adapter Pins 8346 (Fig.
54) to prevent the pulley from rotating.
(7) If water pump is being replaced, do not unbolt
fan blade assembly (Fig. 55) from the thermal control
fan drive.
(8) Remove fan blade/fan drive and fan shroud as
an assembly from vehicle.
After removing fan blade/fan drive assembly,do
notplace the thermal viscous fan drive in the hori-
zontal position. If stored horizontally, the silicone
fluid in the viscous drive could drain into its bearing
assembly and contaminate the bearing lubricant.(9) Remove accessory drive belt (Refer to 7 -
COOLING/ACCESSORY DRIVE/DRIVE BELTS -
REMOVAL) (Fig. 56).
(10) Remove the radiator lower hose at water
pump.
Fig. 54 Using Special Tool 6958 Spanner Wrench
and Adapter Pins 8346
1 - SPECIAL TOOL 6958 SPANNER WRENCH WITH ADAPTER
PINS 8346
2-FAN
Fig. 55 Fan Blade and Viscous Fan DriveÐTypical
1 - WATER PUMP BYPASS HOSE
2 - FAN BLADE ASSEMBLY
3 - VISCOUS FAN DRIVE
4 - WATER PUMP AND PULLEY
Fig. 56 Belt TensionerÐ8.0L V-10 Engine
1 - PULLEY BOLT
2 - IDLER PULLEY
3 - TENSIONER PULLEY
4 - TENSIONER
5 - TENSIONER MOUNTING BOLT
BR/BEENGINE 7 - 71
WATER PUMP - 8.0L (Continued)

AUDIO
TABLE OF CONTENTS
page page
AUDIO
DESCRIPTION............................1
OPERATION.............................2
DIAGNOSIS AND TESTING..................2
AUDIO................................2
SPECIAL TOOLS..........................4
ANTENNA BODY & CABLE
DESCRIPTION............................4
OPERATION.............................4
DIAGNOSIS AND TESTING..................5
ANTENNA.............................5
REMOVAL...............................6
INSTALLATION............................7
RADIO CHOKE RELAY
DESCRIPTION............................8
OPERATION.............................8
DIAGNOSIS AND TESTING..................8
RADIO CHOKE RELAY....................8
REMOVAL...............................9
INSTALLATION............................9
INSTRUMENT PANEL ANTENNA CABLE
REMOVAL...............................9
INSTALLATION...........................10
RADIO
DESCRIPTION...........................10
OPERATION.............................10
DIAGNOSIS AND TESTING.................10
RADIO...............................10
REMOVAL..............................11
INSTALLATION...........................12
RADIO NOISE SUPPRESSION COMPONENTS
DESCRIPTION...........................12
DIAGNOSIS AND TESTING.................12
RADIO NOISE SUPPRESSION
COMPONENTS.........................12ENGINE-TO-BODY GROUND STRAP
REMOVAL..............................13
INSTALLATION...........................13
CAB-TO- BED GROUND STRAP
REMOVAL..............................14
INSTALLATION...........................14
HEATER CORE GROUND STRAP
REMOVAL..............................14
INSTALLATION...........................15
REMOTE SWITCHES
DESCRIPTION...........................15
OPERATION.............................15
DIAGNOSIS AND TESTING.................16
REMOTE SWITCHES....................16
REMOVAL..............................16
INSTALLATION...........................17
SPEAKER
DESCRIPTION...........................17
OPERATION.............................17
DIAGNOSIS AND TESTING.................18
SPEAKER............................18
A-PILLAR TWEETER SPEAKER
REMOVAL..............................19
INSTALLATION...........................19
FRONT DOOR SPEAKER
REMOVAL..............................20
INSTALLATION...........................20
REAR CAB SIDE PANEL SPEAKER
REMOVAL..............................20
INSTALLATION...........................21
REAR DOOR SPEAKER
REMOVAL..............................21
INSTALLATION...........................21
AUDIO
DESCRIPTION
An audio system is standard factory-installed equip-
ment on this model, unless the vehicle is ordered with
an available radio delete option. The standard equip-
ment audio system includes an AM/FM/cassette (RAS
sales code) receiver, and speakers in four locations. Sev-
eral combinations of radio receivers and speaker systems
are offered as optional equipment on this model. The
audio system uses an ignition switched source of battery
current so that the system will only operate when theignition switch is in the On or Accessory positions. The
audio system includes the following components:
²Antenna
²Clockspring (with remote radio switches only)
²Filter, choke and speaker relay (with premium
speaker system only)
²High-line or premium Central Timer Module
(CTM) (with remote radio switches)
²Radio noise suppression components
²Radio receiver
²Remote radio switches (optional with RAZ radio
receiver only)
²Speakers
BR/BEAUDIO 8A - 1

Refer to Electrical, Restraints for more information
on the clockspring. Refer to Electrical, Body Control/
Central Control Module for more information on the
Central Timer Module. Refer to the appropriate wir-
ing information. The wiring information includes wir-
ing diagrams, proper wire and connector repair
procedures, details of wire harness routing and
retention, connector pin-out information and location
views for the various wire harness connectors, splices
and grounds. Following are general descriptions of
the remaining major components in the standard and
optional factory-installed audio systems.
OPERATION
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of each of the available audio systems.
CENTRAL TIMER MODULE
The high-line or premium Central Timer Module
(CTM) can also control some features of the audio
system when the vehicle is equipped with the
optional RAZ radio receiver and remote radio
switches. A high-line CTM is used on high-line ver-
sions of this vehicle. A premium CTM is used on
vehicles equipped with the optional heated seats. The
CTM combines the functions of a chime/buzzer mod-
ule, an intermittent wipe module, an illuminated
entry module, a remote keyless entry module, and a
vehicle theft security system module in a single unit.
The high-line or premium CTM also controls and
integrates many of the additional electronic functions
and features included on models with this option.The RAZ radio receiver with a remote radio switch
option is one of the features that the CTM controls.
The CTM is programmed to send switch status mes-
sages over the Chrysler Collision Detection (CCD)
data bus to control the volume, seek, and pre-set sta-
tion advance functions of the RAZ radio receiver. The
CTM monitors the status of the remote radio
switches located on the steering wheel through a
hard wired circuit. The CTM then sends the proper
switch status messages to the radio receiver. The
electronic circuitry within the radio receiver responds
to the switch status messages it receives by adjusting
the radio settings as requested.
Refer to Electrical, Body Control/Central Timer
Module for more information on the high-line CTM.
Refer to Remote Radio Switch in Description and
Operation for more information on this component.
In addition, radio receivers connected to the CCD
data bus have several audio system functions that
can be diagnosed using a DRBIIItscan tool. Refer to
the proper Diagnostic Procedures manual for more
information on DRBIIIttesting of the audio systems.
DIAGNOSIS AND TESTING - AUDIO
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING ANY STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
8A - 2 AUDIOBR/BE
AUDIO (Continued)

Audio System Diagnosis
CONDITION POSSIBLE CAUSE CORRECTION
NO AUDIO 1. Fuse faulty. 1. Check radio fuses in junction block. Replace faulty fuses, if
required.
2. Radio connector faulty. 2. Check for loose or corroded radio connections. Repair, if
required.
3. Wiring faulty. 3. Check for battery voltage at radio connector. Repair wiring,
if required.
4. Ground faulty. 4. Check for continuity between radio chassis and a known
good ground. There should be continuity. Repair ground, if
required.
5. Radio faulty. 5. Refer to Radio in the Diagnosis and Testing section of this
group.
6. Speakers faulty. 6. Refer to Speaker in the Diagnosis and Testing section of
this group.
7. Amplifier faulty (if
equipped).7. Refer to Speaker in the Diagnosis and Testing section of
this group.
NO DISPLAY 1. Fuse faulty. 1. Check radio fuses in junction block. Replace faulty fuses, if
required.
2. Radio connector faulty. 2. Check for loose or corroded radio connections. Repair, if
required.
3. Wiring faulty. 3. Check for battery voltage at radio connector. Repair wiring,
if required.
4. Ground faulty. 4. Check for continuity between radio chassis and a known
good ground. There should be continuity. Repair ground, if
required.
5. Radio faulty. 5. Refer to Radio in the Diagnosis and Testing section of this
group.
CLOCK WILL NOT
KEEP SET TIME1. Fuse faulty. 1. Check ignition-off draw fuse. Replace faulty fuse, if
required.
2. Radio connector faulty. 2. Check for loose or corroded radio connections. Repair, if
required.
3. Wiring faulty. 3. Check for battery voltage at radio connector. Repair wiring,
if required.
4. Ground faulty. 4. Check for continuity between radio chassis and a known
good ground. There should be continuity. Repair ground, if
required.
5. Radio faulty. 5. Refer to Radio in the Diagnosis and Testing section of this
group.
POOR RADIO
RECEPTION1. Antenna faulty. 1. Refer to Antenna in the Diagnosis and Testing section of
this group.
2. Ground faulty. 2. Check for continuity between radio chassis and a known
good ground. There should be continuity. Repair ground, if
required.
3. Radio faulty. 3. Refer to Radio in the Diagnosis and Testing section of this
group.
4. Faulty EMI or RFI
noise suppression.4. Refer to Radio Frequency Interference in the Diagnosis
and Testing section of this group.
BR/BEAUDIO 8A - 3
AUDIO (Continued)

(7) Remove the radio receiver from the instrument
panel. Refer to Audio, Radio for the procedures.
(8) Pull the antenna cable out through the radio
receiver opening in the instrument panel.
(9) Untie the cord or twine from the instrument
panel antenna cable connector, leaving the cord or
twine in place of the cable in the instrument panel.
(10) Remove the antenna cable from the instru-
ment panel.
INSTALLATION
(1) Tie the end of the cord or twine that was used
during instrument panel antenna cable removal
securely to the connector on the end of the antenna
cable being installed into the instrument panel. This
cord will be used to pull or ªfishº the cable back into
position.
(2) Using the cord or twine, pull the antenna cable
through the radio receiver opening from under the
instrument panel.
(3) Install the radio receiver onto the instrument
panel. Refer to Audio, Radio for the procedures.
(4) Reach through the glove box opening to engage
the antenna cable with the retainer clips on the back
of the instrument panel.
(5) Install the glove box onto the instrument panel.
Refer to Body, Instrument Panel for the procedures.
(6) Untie the cord or twine from the instrument
panel antenna cable connector.
(7) Reach under the passenger side of the instru-
ment panel near the right cowl side inner panel to
reconnect the two halves of the radio antenna coaxial
cable connector. Wrap the connection with a piece of
foam tape.
(8) Engage the coaxial cable connector with the
retainer clip located on the bottom of the heater-A/C
housing.
(9) Reconnect the battery negative cable.
RADIO
DESCRIPTION
Available factory-installed radio receivers for this
model include an AM/FM/cassette (RAS sales code),
an AM/FM/cassette/5-band graphic equalizer with CD
changer control feature (RBN sales code), an AM/FM/
CD/3-band graphic equalizer (RBR sales code), or an
AM/FM/CD/cassette/3-band graphic equalizer (RAZ
sales code). The factory-installed RAZ sales code
radio receivers can also communicate on the Chrysler
Collision Detection (CCD) data bus network through
a separate two-way wire harness connector. All facto-
ry-installed receivers are stereo Electronically Tuned
Radios (ETR) and include an electronic digital clock
function.These radio receivers can only be serviced by an
authorized radio repair station. See the latest War-
ranty Policies and Procedures manual for a current
listing of authorized radio repair stations.
All vehicles are equipped with an Ignition-Off
Draw (IOD) fuse that is removed when the vehicle is
shipped from the factory. This fuse feeds various
accessories that require battery current when the
ignition switch is in the Off position, including the
clock. The IOD fuse is removed to prevent battery
discharge during vehicle storage.
When removing or installing the IOD fuse, it is
important that the ignition switch be in the Off posi-
tion. Failure to place the ignition switch in the Off
position can cause the radio display to become scram-
bled when the IOD fuse is removed and replaced.
Removing and replacing the IOD fuse again, with the
ignition switch in the Off position, will correct the
scrambled display condition.
The IOD fuse should be checked if the radio or
clock displays are inoperative. The IOD fuse is
located in the junction block. Refer to the fuse layout
label on the back of the instrument panel fuse access
panel for IOD fuse identification and location.
OPERATION
The radio receiver operates on fused battery cur-
rent that is available only when the ignition switch is
in the On or Accessory positions. The electronic digi-
tal clock function of the radio operates on fused bat-
tery current supplied through the IOD fuse,
regardless of the ignition switch position.
For more information on the features, setting pro-
cedures, and control functions for each of the avail-
able factory-installed radio receivers, see the owner's
manual in the vehicle glove box. For complete circuit
diagrams, refer to the appropriate wiring informa-
tion. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
details of wire harness routing and retention, connec-
tor pin-out information and location views for the
various wire harness connectors, splices and grounds.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - RADIO
If the vehicle is equipped with the optional remote
radio switches located on the steering wheel and the
problem being diagnosed is related to one of the
symptoms listed below, be certain to check the
remote radio switches and circuits. Refer to Audio,
Remote Radio Switch prior to attempting radio diag-
nosis or repair.
²Stations changing with no remote radio switch
input
8A - 10 AUDIOBR/BE
INSTRUMENT PANEL ANTENNA CABLE (Continued)

(6) Remove the heater core ground strap from the
top of the heater-A/C housing.
INSTALLATION
(1) Position the heater core ground strap and the
heater core tube retaining strap to the top of the
heater-A/C housing.
(2) Install and tighten the screw that secures the
heater core ground strap eyelet and the heater core
tube retaining strap to the top of the heater-A/C
housing. Tighten the screw to 2.2 N´m (20 in. lbs.).
(3) Position the heater core ground strap eyelet
over the stud on the dash panel.
(4) Install and tighten the nut that secures the
heater core ground strap eyelet to the stud on the
dash panel. Tighten the nut to 3.9 N´m (35 in. lbs.).
(5) Install the glove box onto the instrument panel.
Refer to Body, Instrument Panel for the procedures.
(6) Reconnect the battery negative cable.
REMOTE SWITCHES
DESCRIPTION
A remote radio switch option is available on models
equipped with the AM/FM/CD/cassette/3-band
graphic equalizer (RAZ sales code) radio receiver and
the high-line Central Timer Module (CTM). Refer to
Electrical, Body Control/Central Timer Module for
more information on this component.
Two rocker-type switches (Fig. 15) are mounted in
the sides of the rear (instrument panel side) steeringwheel trim cover. The switch on the left side is the
seek switch and has seek up, seek down, and preset
station advance functions. The switch on the right
side is the volume control switch and has volume up,
and volume down functions. The two switches are
retained in mounting holes located on each side of
the rear steering wheel trim cover by four latches
that are integral to the switches.
The remote radio switches share a common steer-
ing wheel wire harness with the vehicle speed control
switches. The steering wheel wire harness is con-
nected to the instrument panel wire harness through
the clockspring. Refer to Electrical, Clockspring for
more information on this component.
OPERATION
The remote radio switches are resistor multiplexed
units that are hard wired to the high-line or pre-
mium CTM through the clockspring. The CTM mon-
itors the status of the remote radio switches and
sends the proper switch status messages on the
Chrysler Collision Detection (CCD) data bus network
to the radio receiver. The electronic circuitry within
the radio is programmed to respond to these remote
radio switch status messages by adjusting the radio
settings as requested.
For diagnosis of the CTM or the CCD data bus, the
use of a DRBIIItscan tool and the proper Diagnostic
Procedures manual are recommended. For more
information on the features and control functions for
each of the remote radio switches, see the owner's
Fig. 14 Heater Core Ground Strap Remove/Install
1 - GROUND STRAP
2 - NUT
3 - HEATER-A/C HOUSING
4 - DASH PANEL
Fig. 15 Remote Radio Switches
1 - PRESET SEEK
2-UP
3 - SEEK
4 - VOLUME
5 - DOWN
BR/BEAUDIO 8A - 15
HEATER CORE GROUND STRAP (Continued)

removed). Then continue to slowly rotate engine
clockwise until indicating mark (Fig. 18) is aligned to
0 degree (TDC) mark on timing chain cover.
(1) Clean top of cylinder block for a good seal
between distributor base and block.
(2) Lightly oil the rubber o-ring seal on the distrib-
utor housing.
(3) Install rotor to distributor shaft.
(4) Position distributor into engine to its original
position. Engage tongue of distributor shaft with slot
in distributor oil pump drive gear. Position rotor to
the number one spark plug cable position.
(5) Install distributor holddown clamp and clamp
bolt. Do not tighten bolt at this time.(6) Rotate the distributor housing until rotor is
aligned to CYL. NO. 1 alignment mark on the cam-
shaft position sensor (Fig. 19) .
(7) Tighten clamp holddown bolt (Fig. 20) to 22.5
N´m (200 in. lbs.) torque.
(8) Connect camshaft position sensor wiring har-
ness to main engine harness.
(9) Install distributor cap. Tighten mounting
screws.
(10) Refer to the following, Checking Distributor
Position.
Checking Distributor Position
To verify correct distributor rotational position, the
DRB scan tool must be used.
WARNING: WHEN PERFORMING THE FOLLOWING
TEST, THE ENGINE WILL BE RUNNING. BE CARE-
FUL NOT TO STAND IN LINE WITH THE FAN
BLADES OR FAN BELT. DO NOT WEAR LOOSE
CLOTHING.
(1) Connect DRB scan tool to data link connector.
The data link connector is located in passenger com-
partment, below and to left of steering column.
(2) Gain access to SET SYNC screen on DRB.
(3) Follow directions on DRB screen and start
engine. Bring to operating temperature (engine must
be in ªclosed loopº mode).
(4) With engine running atidle speed, the words
IN RANGE should appear on screen along with 0É.
This indicates correct distributor position.
(5) If a plus (+) or a minus (-) is displayed next to
degree number, and/or the degree displayed is not
zero, loosen but do not remove distributor holddown
clamp bolt. Rotate distributor until IN RANGE
appears on screen. Continue to rotate distributor
until achieving as close to 0É as possible. After
adjustment, tighten clamp bolt to 22.5 N´m (200 in.
lbs.) torque.
The degree scale on SET SYNC screen of DRB is
referring to fuel synchronization only.It is not
referring to ignition timing.Because of this, do
not attempt to adjust ignition timing using this
method. Rotating distributor will have no effect on
ignition timing. All ignition timing values are con-
trolled by powertrain control module (PCM).
After testing, install air cleaner assembly.
DISTRIBUTOR CAP
DIAGNOSIS AND TESTING - DISTRIBUTOR
CAP
Remove the distributor cap and wipe it clean with
a dry lint free cloth. Visually inspect the cap for
cracks, carbon paths, broken towers or damaged
Fig. 19 Rotor Alignment Mark
1 - CAMSHAFT POSITION SENSOR ALIGNMENT MARK
2 - ROTOR
3 - DISTRIBUTOR
Fig. 20 Distributor Holddown Clamp
1 - CLAMP BOLT
2 - HOLDDOWN CLAMP
3 - DISTRIBUTOR HOUSING
8I - 12 IGNITION CONTROLBR/BE
DISTRIBUTOR (Continued)

causing the PCM's output brake signal to go high,
disengaging the speed control, cutting off PCM power
to the speed control solenoids.
The second set of normally closed contacts supplies
12 volts from the PCM any time speed control is
turned on. Through the brake switch, current is
routed to the speed control servo solenoids. The
speed control solenoids (vacuum, vent and dump) are
provided this current any time the speed control is
ON and the brakes are disengaged.
When the driver applies the brakes, the contacts
open and current is interrupted to the solenoids. The
normally open contacts are fed battery voltage. When
the brakes are applied, battery voltage is supplied to
the brake lamps.
DIAGNOSIS AND TESTING - BRAKE LAMP
SWITCH
The brake lamp switch can be tested with an ohm-
meter. The ohmmeter is used to check continuity
between the pin terminals (Fig. 1).
SWITCH CIRCUIT IDENTIFICATION
²Terminals 1 and 2: brake lamp circuit
²Terminals 3 and 4: RWAL/ABS module and Pow-
ertrain Control Module (PCM) circuit
²Terminals 5 and 6: speed control circuit
SWITCH CONTINUITY TEST
NOTE: Disconnect switch harness before testing
switch continuity.
With switch plunger extended, attach test leads to
pins 1 and 2. Replace switch if meter indicates no
continuity.With switch plunger retracted, attach test leads to
pins 3 and 4. Replace switch if meter indicates no
continuity.
With switch plunger retracted, attach test leads to
pins 5 and 6. Replace switch if meter indicates no
continuity.
REMOVAL
(1) Remove knee bolster for access to brake lamp
switch and pedal.
(2) Disconnect switch harness (Fig. 2) .
(3) Press and hold brake pedal in applied position.
(4) Rotate switch counterclockwise about 30É to
align switch lock tabs with notch in bracket.
(5) Pull switch rearward out of mounting bracket
and release brake pedal.
INSTALLATION
(1) Connect harness wires tonewswitch.
(2) Press and hold brake pedal down.
(3) Install switch. Align tabs on switch with
notches in switch bracket (Fig. 3). Then insert switch
in bracket and turn it clockwise approximately 30É to
lock it in place.
(4) Release brake pedal. Then move the release
lever on the switch to engage the switch plunger. The
switch is now adjusted and can not be adjusted
again.
(5) Install the knee bolster.
Fig. 1 Brake Lamp Switch Terminal Identification
1 - TERMINAL PINS
2 - PLUNGER TEST POSITIONS
Fig. 2 Brake Lamp Switch & Harness Connector
1 - BRAKE LIGHT SWITCH
2 - SWITCH BRACKET
3 - HARNESS CONNECTOR
4 - SWITCH LEVER
BR/BELAMPS/LIGHTING - EXTERIOR 8L - 5
BRAKE LAMP SWITCH (Continued)

REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Unplug the wire harness connector from the
automatic day/night mirror (Fig. 2).
(3) Remove the set screw that secures the auto-
matic day/night mirror to the windshield support
button.
(4) Push the automatic day/night mirror upwards
far enough for the mounting bracket to clear the sup-
port button and remove the mirror from the wind-
shield.
INSTALLATION
(1) Install the mirror to the support button.
(2) Tighten the set screw.
(3) Reconnect the harness connector to the mirror.
(4) Reconnect the negative battery cable.
POWER MIRROR SWITCH
DESCRIPTION
Both the right and left power outside mirrors are
controlled by a single multi-function switch unit
located on and mounted to the upper flag area of the
driver side door trim panel.
OPERATION
The switch knob is rotated clockwise (right mirror
control), or counterclockwise (left mirror control) to
select the mirror to be adjusted. The switch knob is
then moved in a joystick fashion to control movement
of the selected mirror up, down, right, or left.
The power mirror switch cannot be repaired and, if
faulty or damaged, it must be replaced. The power
mirror switch knob is available for service replace-
ment.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Pull the control knob rearward to remove it
from the power mirror switch stem (Fig. 3).
Fig. 2 AUTOMATIC DAY/NIGHT MIRROR REMOVE
1 - SCREW
2 - WIRE HARNESS CONNECTOR
3 - AUTOMATIC DAY/NIGHT MIRROR
4 - SUPPORT BUTTON
Fig. 3 POWER MIRROR SWITCH REMOVE/INSTALL
1 - DOOR
2 - SWITCH
3 - DOOR TRIM PANEL
4 - KNOB
5 - NUT
8N - 12 POWER MIRRORSBR/BE
AUTOMATIC DAY / NIGHT MIRROR (Continued)

HYDRAULIC LIFTERS (CAM IN
BLOCK)
DIAGNOSIS AND TESTINGÐHYDRAULIC
TAPPETS
Before disassembling any part of the engine to cor-
rect tappet noise, check the oil pressure. If vehicle
has no oil pressure gauge, install a reliable gauge at
the pressure sending-unit. The pressure should be
between 207-552 kPa (30-80 psi) at 3,000 RPM.
Check the oil level after the engine reaches normal
operating temperature. Allow 5 minutes to stabilize
oil level, check dipstick. The oil level in the pan
should never be above the FULL mark or below the
ADD OIL mark on dipstick. Either of these two con-
ditions could be responsible for noisy tappets.
OIL LEVEL
HIGH
If oil level is above the FULL mark, it is possible
for the connecting rods to dip into the oil. With the
engine running, this condition could create foam in
the oil pan. Foam in oil pan would be fed to the
hydraulic tappets by the oil pump causing them to
lose length and allow valves to seat noisily.
LOW
Low oil level may allow oil pump to take in air.
When air is fed to the tappets, they lose length,
which allows valves to seat noisily. Any leaks on
intake side of oil pump through which air can be
drawn will create the same tappet action. Check the
lubrication system from the intake strainer to the
pump cover, including the relief valve retainer cap.
When tappet noise is due to aeration, it may be
intermittent or constant, and usually more than one
tappet will be noisy. When oil level and leaks have
been corrected, operate the engine at fast idle. Run
engine for a sufficient time to allow all of the air
inside the tappets to be bled out.
TAPPET NOISE DIAGNOSIS
(1) To determine source of tappet noise, operate
engine at idle with cylinder head covers removed.
(2) Feel each valve spring or rocker arm to detect
noisy tappet. The noisy tappet will cause the affected
spring and/or rocker arm to vibrate or feel rough in
operation.
NOTE: Worn valve guides or cocked springs are
sometimes mistaken for noisy tappets. If such is
the case, noise may be dampened by applying side
thrust on the valve spring. If noise is not apprecia-
bly reduced, it can be assumed the noise is in thetappet. Inspect the rocker arm push rod sockets
and push rod ends for wear.
(3) Valve tappet noise ranges from light noise to a
heavy click. A light noise is usually caused by exces-
sive leak-down around the unit plunger, or by the
plunger partially sticking in the tappet body cylinder.
The tappet should be replaced. A heavy click is
caused by a tappet check valve not seating, or by for-
eign particles wedged between the plunger and the
tappet body. This will cause the plunger to stick in
the down position. This heavy click will be accompa-
nied by excessive clearance between the valve stem
and rocker arm as valve closes. In either case, tappet
assembly should be removed for inspection and clean-
ing.
(4) The valve train generates a noise very much
like a light tappet noise during normal operation.
Care must be taken to ensure that tappets are mak-
ing the noise. If more than one tappet seems to be
noisy, it's probably not the tappets.
LEAK-DOWN TEST
After cleaning and inspection, test each tappet for
specified leak-down rate tolerance to ensure zero-lash
operation (Fig. 38).
Swing the weighted arm of the hydraulic valve tap-
pet tester away from the ram of the Universal Leak-
Down Tester.
(1) Place a 7.925-7.950 mm (0.312-0.313 inch)
diameter ball bearing on the plunger cap of the tap-
pet.
(2) Lift the ram and position the tappet (with the
ball bearing) inside the tester cup.
(3) Lower the ram, then adjust the nose of the ram
until it contacts the ball bearing. DO NOT tighten
the hex nut on the ram.
(4) Fill the tester cup with hydraulic valve tappet
test oil until the tappet is completely submerged.
(5) Swing the weighted arm onto the push rod and
pump the tappet plunger up and down to remove air.
When the air bubbles cease, swing the weighted arm
away and allow the plunger to rise to the normal
position.
(6) Adjust the nose of the ram to align the pointer
with the SET mark on the scale of the tester and
tighten the hex nut.
(7) Slowly swing the weighted arm onto the push
rod.
(8) Rotate the cup by turning the handle at the
base of the tester clockwise one revolution every 2
seconds.
(9) Observe the leak-down time interval from the
instant the pointer aligns with the START mark on
the scale until the pointer aligns with the 0.125
mark. A normally functioning tappet will require
9 - 38 ENGINE 3.9LBR/BE