timing belt JEEP CHEROKEE 1988 Service Repair Manual
[x] Cancel search | Manufacturer: JEEP, Model Year: 1988, Model line: CHEROKEE, Model: JEEP CHEROKEE 1988Pages: 1378, PDF Size: 19.9 MB
Page 406 of 1378
DRIV E B ELT R O UTIN G
1988 J e ep C hero ke e
1983-88 ENGINE COOLING
Jeep Drive Belt Routing
Cherokee, Comanche, Wagoneer, Wrangler, Grand Wagoneer
DESCRIPTION
Two drive belt systems are used on Jeep vehicles. The
conventional V-Belt and the single Serpentine or V-Ribbed belt.
The single (Serpentine or V-Ribbed) drive belt system
has been adopted by several manufacturers as a replacement for
multiple V-Belt systems previously offered. The Serpentine belt
requires a suitable belt tensioner similar to those used to control
timing belt tension.
Use of a tensioner allows engine accessories to be mounted
rigidly on the engine. The single belt drive system has a predicted
life of 100,000 miles before replacement is required.
The belt tensioner has a wide functional range and is
capable of maintaining tension during the expected life of the belt.
Tensioner cannot compensate for extreme belt lengths. Poor tension
control and possible tensioner damage can result from excessive belt
length.
INSPECTION
Inspect belt for fraying. If fraying has occurred, ensure
belt and tensioner are aligned properly. See Fig. 1. If tensioner has
reached its limit of travel, belt is excessively stretched and
replacement of belt is required. If excessive noise is noticed from
tensioner or idler, check for possible bearing failure. Small cracks
in the back of the belt are acceptable. Do not apply "Belt Dressing"
or any other additive to serpentine belt.
Fig. 1: Serpentine Belt Alignment
Courtesy of Ford Motor Co.
DRIVE BELT ROUTING
Page 638 of 1378
NOTE: Always refer to appropriate engine overhaul article in the
ENGINES section for complete overhaul procedures and
specifications for the vehicle being repaired.
CLEANING & INSPECTION
Clean camshaft with solvent. Ensure all oil passages are
clear. Inspect cam lobes and bearing journals for pitting, flaking or
scoring. Using micrometer, measure bearing journal O.D.
Support camshaft at each end with "V" blocks. Position dial
indicator with tip resting on center bearing journal. Rotate camshaft
and note reading. If reading exceeds specification, replace camshaft.
Check cam lobe lift by measuring base circle of camshaft
using micrometer. Measure again at 90 degrees to tip of cam lobe. Cam
lift can be determined by subtracting base circle diameter from tip of
cam lobe measurement.
Different lift dimensions are given for intake and exhaust
cam lobes. Reading must be within specifications. Replace camshaft if
cam lobes or bearing journals are not within specifications.
Inspect camshaft gear for chipped, eroded or damaged teeth.
Replace gear if damaged. On camshafts using thrust plate, measure
distance between thrust plate and camshaft shoulder. Replace thrust
plate if not within specification.
CAMSHAFT BEARINGS
Removal & Installation
Remove the camshaft rear plug. The camshaft bearing remover
is assembled with its shoulder resting on the bearing to be removed
according to manufacturer's instructions. Tighten puller nut until
bearing is removed. Remove remaining bearings, leaving front and rear
bearings until last. These bearings act as guide for camshaft bearing
remover.
To install new bearings, puller is rearranged to pull
bearings toward the center of block. Ensure all lubrication passages
of bearing are aligned with cylinder block. Coat new camshaft rear
plug with sealant. Install camshaft rear plug. Ensure plug is even
in cylinder block.
CAMSHAFT INSTALLATION
Lubricate bearing surfaces and cam lobes with ample amount of
Molykote or camshaft lubricant. Carefully install camshaft. Use care
not to damage bearing journals during installation. Install thrust
plate retaining bolts (if equipped). Tighten bolts to specification.
On overhead camshafts, install bearing caps in original location.
Tighten bolts to specification. Check end play.
CAMSHAFT END PLAY
Using dial indicator, check end play. Position dial indicator
on front of engine block. Position indicator tip against camshaft.
Push camshaft toward rear of engine and adjust indicator to zero.
Move camshaft forward and note reading. Camshaft end play
must be within specification. End play may be adjusted by relocating
gear, shimming thrust plate or replacing thrust plate depending on
manufacturer.
TIMING CHAINS & BELTS
Page 640 of 1378
manufacturer. See Fig. 24.
Fig. 24: Timing Gear Mark Alignment - Typical
This Graphic For General Information Only
TIMING BELTS
Cogged tooth belts are commonly used on overhead cam
engines. Inspect belt teeth for rounded corners or cracking. Replace
belt if cracked, damaged, missing teeth or oil soaked.
Used timing belt must be installed in original direction of
rotation. Inspect all sprocket teeth for wear. Replace all worn
sprockets. Sprockets are marked for timing purposes. Engine is
positioned so that crankshaft sprocket mark will be upward. Camshaft
sprocket is aligned with reference mark on cylinder head and timing
belt is installed. See Fig. 25.
Page 641 of 1378
Fig. 25: Timing Belt Sprocket Alignment - Typical
This Graphic For General Information Only
TENSION ADJUSTMENTS
If guide rails are used with spring loaded tensioners,
ensure at least half of original rail thickness remains. Spring
loaded tensioner should be inspected for damage.
Ensure all timing marks are aligned. Adjust belt tension
using manufacturer's recommendations. Belt tension may require
checking using tension gauge. See Fig. 26.
Page 642 of 1378
Fig. 26: Timing Belt Tension Adjustment - Typical
This Graphic For General Information Only
TIMING GEARS
Page 656 of 1378
SUPER CHARGERS
SWITCHES
THERMAL VACUUM VALVES
THERMOSTATIC AIR DOOR ASSEMBLIES
THERMOSTATS AND HOUSINGS
THROTTLE BODIES
THROTTLE CABLES
THROTTLE LINKAGES AND CABLES
THROTTLE POSITION SENSORS
THROTTLE POSITION SWITCHES
TIMING BELT SPROCKETS
TIMING BELTS
TORQUE STRUTS
TRANSMISSION RANGE SWITCHES
TUBE CLAMPS
TUBE CONNECTORS
TUBE COUPLERS
TUBES
TURBO CHARGERS
VACUUM CONNECTIONS
VACUUM HOSES, TUBES AND CONNECTIONS (NON-METALLIC)
VACUUM REGULATOR SOLENOIDS
VACUUM TUBES
VEHICLE SPEED SENSORS
VOLUME AIR FLOW SENSORS
WASTE GATE CONTROL SOLENOIDS
WASTE GATES AND BOOST CONTROL MECHANISMS
WATER PUMPS (ELECTRIC)
WATER PUMPS (NON-ELECTRIC)
WIRING HARNESSES AND CONNECTORS
INTRODUCTION TO MOTORIST ASSURANCE PROGRAM (MAP)
OVERVIEW OF MOTORIST ASSURANCE PROGRAM
The Motorist Assurance Program is the consumer outreach
effort of the Automotive Maintenance and Repair Association, Inc.
(AMRA). Participation in the Motorist Assurance Program is drawn from
retailers, suppliers, independent repair facilities, vehicle
manufacturers and industry associations.
Our organization's mission is to strengthen the relationship
between the consumer and the auto repair industry. We produce
materials that give motorists the information and encouragement to
take greater responsibility for their vehicles-through proper,
manufacturer-recommended, maintenance. We encourage participating
service and repair shops (including franchisees and dealers) to adopt
(1) a Pledge of Assurance to their Customers and (2) the Motorist
Assurance Program Standards of Service. All participating service
providers have agreed to subscribe to this Pledge and to adhere to the
promulgated Standards of Service demonstrating to their customers that
they are serious about customer satisfaction.
These Standards of Service require that an inspection of the
vehicle's (problem) system be made and the results communicated to the\
customer according to industry standards. Given that the industry did
not have such standards, the Motorist Assurance Program successfully
promulgated industry inspection communication standards in 1994-95 for
the following systems: Exhaust, Brakes, ABS, Steering and Suspension,
Engine Maintenance and Performance, HVAC, and Electrical Systems.
Further, revisions to all of these inspection communication standards
are continually re-published. In addition to these, standards for
Drive Train and Transmissions have recently been promulgated.
Participating shops utilize these Uniform Inspection & Communication
Page 747 of 1378
Threads stripped (threads
missing) ............... A ............ Require replacement.
Wire lead conductors
exposed ................ B .. Require repair or replacement.
Wire lead corroded ...... A .. Require repair or replacement.
Wire lead open .......... A .. Require repair or replacement.
Wire lead shorted ....... A .. Require repair or replacement.
(1) - Determine cause and correct prior to repair or
replacement of part.
( 2) - Inoperative includes intermittent operation or out of
OEM specification. Some components may be serviceable;
check for accepted cleaning procedure.
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TIMING BELT SPROCKETS
TIMING BELT SPROCKET INSPECTION \
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Condition Code Procedure
Alignment incorrect ..... B ................. Require repair.
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Bent .................... A ............ Require replacement.
Cracked ................. A ............ Require replacement.
Key damaged ............. A ............ Require replacement.
Loose ................... A .. Require repair or replacement.
Missing ................. C ............ Require replacement.
Pulley damaged, affecting
belt life .............. A ............ Require replacement.
Sprocket damaged,
affecting belt life .... A .. Require repair or replacement.
Sprocket loose .......... B .. Require repair or replacement.
Sprocket-to-shaft
alignment incorrect ..... B .. Require repair or replacement.
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TIMING BELTS
TIMING BELT INSPECTION \
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Condition Code Procedure
Adjustment incorrect .... 2 ......... ( 1) Suggest adjustment.
Alignment incorrect ..... B ........... ( 2) Further inspection
required.
Broken .................. A ............ Require replacement.
Cam timing out of
specification .......... B ................. Require repair.
Cracked ................. 1 ............ Suggest replacement.
Fluid-soaked ............ 1 ... Suggest replacement. Further
inspection required.
Frayed .................. 1 ............ Suggest replacement.
Maintenance intervals ... 3 ... Suggest replacement to comply
with vehicle OEM recommended
Page 748 of 1378
service intervals.
Missing ................. C ........ (3) Require replacement.
Noisy ................... 2 .......... ( 4) Further inspection
required.
See note below.
Plies separated ......... A ............ Require replacement.
Tension out of
specification .......... B ........... Require adjustment or
replacement.
Teeth missing ........... A ............ Require replacement.
( 1) - Inspect belt tensioners, pulleys, and cover.
( 2) - Determine cause of incorrect alignment and require repair.
( 3) - CAUTION: Internal engine damage may result from timing
belt damage/failure.
( 4) - Determine cause of noise and suggest repair.
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TORQUE STRUTS
TORQUE STRUT INSPECTION \
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Condition Code Procedure
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Binding ................. A ............ Require replacement.
Body dented ............. A .......... ( 1) Further inspection
required.
Body punctured .......... A ............ Require replacement.
Bushing deteriorated,
affecting performance .. A ............ Require replacement.
Bushing deteriorated, not
affecting performance .. .. ........ No service suggested or
required.
Bushings missing ........ C ............ Require replacement.
Bushings separated from
mounting eye ........... 1 ............ Suggest replacement.
Damping (none) .......... A ............ Require replacement.
Leaking oil, enough for
fluid to be running down
the body ............... A ............ Require replacement.
Missing ................. C ............ Require replacement.
Noisy ................... 2 .......... ( 2) Further inspection
required.
Piston rod bent ......... A ............ Require replacement.
Piston rod broken ....... A ............ Require replacement.
Seized .................. A ............ Require replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ............ Require replacement.
( 1) - Require replacement of units where dents restrict strut
piston rod movement. If dents don't restrict movement, no
service is suggested or required.
( 2) - If noise is isolated to shock or strut, suggest replacement.
Page 904 of 1378
* Cold Climate Operation
* Towing Or Heavily Loading
* Severe Dust Conditions
* Sustained High Speed Operation
* Off-Road Driving
* Hot Weather, Stop-And-Go Driving
* Extensive Idling Conditions (Taxi Or Delivery Type Service)
Normal Service
* Driven More Than 10 Miles Daily
* No Severe Service Operating Conditions
CAMSHAFT TIMING BELT REPLACEMENT INFORMATION (TURBO-DIESEL)
CAUTION: Failure to replace a faulty camshaft timing belt may result
in serious engine damage.
The condition of camshaft drive belts should always be
checked on vehicles which have more than 50,000 miles. Although some
manufacturers do not recommend belt replacement at a specified
mileage, others require it at 60,000-100,000 miles. A camshaft drive
belt failure may cause extensive damage to internal engine components
on most engines, although some designs do not allow piston-to-valve
contact. These designs are often called "Free Wheeling".
Many manufacturers changed their maintenance and warranty
schedules in the mid-1980's to reflect timing belt inspection and/or
replacement at 50,000-60,000 miles. Most service interval schedules
reflect these changes.
Belts or components should be inspected and replaced if any
of the following conditions exist:
* Cracks Or Tears In Belt Surface
* Missing, Damaged, Cracked Or Rounded Teeth
* Oil Contamination
* Damaged Or Faulty Tensioners
* Incorrect Tension Adjustment
SERVICE LABOR TIMES
SERVICE LABOR TIMES TABLE (HOURS)\
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( 1) 30,000 60,000
Application Mile Service Mile Service
2.1L (Turbo Diesel)
Automatic Transmission ........... 4.3 ................ 4.5
Manual Transmission .............. 3.6 ................ 3.8
2.5L
Automatic Transmission ........... 5.6 ................ 3.5
Manual Transmission .............. 4.9 ................ 3.5
2.8L
Automatic Transmission ........... 5.8 ................ 3.7
Manual Transmission .............. 5.1 ................ 3.7
4.0L
Automatic Transmission ........... 5.7 ................ 3.6
Manual Transmission .............. 5.0 ................ 3.6
( 1) - Add .8 hr. for vehicles equipped with 4WD.
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Choke Linkage
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Ignition Timing
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Lubricate Manifold Heat Control Valve (if equipped)
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Clean PCV Breather (if equipped)
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Clean EGR Passages (if equipped)
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Inspect C/V Joint boots (4WD)
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Inspect Underside of Vehicle (Bolts & Threaded Fasteners)
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Check/Lube Manual Steering Gear
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Check Drive Shaft Seals
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Lubricate Ball Joints, Steering Linkage & Suspension
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Lube Drive Shaft U-Joints and Slip Splines
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Lube Front Axle Drive Joint and Pivot Bearings (4WD)
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Inspect Front Wheel Bearings (4WD)
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Suspension Bushings, Springs, Arms & Rear Jounce Bumpers
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Parking Brake System
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Inspect Shocks for Leakage
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Inspect Tire Wear Pattern
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Rotate Tires and Adjust Air Pressure (Including Spare)
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Replace
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Engine Oil
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Oil Filter
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Spark Plugs
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Ignition Cables
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Distributor Cap and Rotor
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Air Filter Element
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EGR Valve & Tube (1987-92)
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PCV Valve (
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Drive Belt (V-Type) (
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Flush and Fill Engine Coolant, if not done in last 24 months
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Automatic Transmission Fluid, Filter and Adjust Bands
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Accessory Drive Belts