Dusty Conditions
Driving through dust-laden air increases the problems of
keeping abrasive materials out of the engine. Under these
conditions, special attention should be given to the
engine air cleaner and the crankcase inlet air cleaner. The
crankcase ventilation system should also be checked
periodically. Make sure that these units are always clean.
This will tend to reduce to a minimum the amount of
abrasive material that may enter the engine.
Engine Oil Selection
For best performance and maximum protection under all
types of operating conditions, the manufacture only
recommends engine oils that are API certified and meet
the requirements of DaimlerChrysler Material Standard
MS-6395. Use Mopar or an equivalent oil meeting the
specification MS-6395.
American Petroleum Institute (API) Oil
Identification Symbol
There is a symbol to aid you in selecting the proper
engine oil.This symbol means that the oil has
been certified by the American
Petroleum Institute (API). The
manufacture only recommends
API Certified engine oils that
meet the requirements of
DaimlerChrysler Material Stan-
dard MS-6395. Use Mopar or an
equivalent oil meeting the specifi-
cation MS-6395.
Engine Oil Viscosity Chart
The proper SAE viscosity grade of engine oil should be
selected based on the following recommendation and be
within the operating temperature shown in the recom-
mended SAE viscosity chart.
²SAE 5W-30 is the oil recommended in trucks equipped
with a 3.7L/4.7L engine, for optimum fuel economy.
²Synthetic engine oils may be used provided that the oil
quality requirements described above are met and the
recommended maintenance intervals for oil and filter
changes are followed.
228 MAINTAINING YOUR VEHICLE
quality filters should be used to assure most efficient
service. Mopar Engine Oil Filters are a high quality oil
filter and are recommended.
Drive Belts Ð Check Condition and Tension
At the mileage indicated in the maintenance schedule, all
belts should be checked for condition and proper tension.
Improper belt tension can cause belt slippage and failure.
Belts should be inspected for evidence of cuts, cracks, or
glazing, and replaced if there is indication of damage
which could result in belt failure. If adjustment is re-
quired, see your authorized dealer for service. Low
generator belt tension can cause battery failure. A special
tool is required to properly measure tension and to
restore belt tension to factory specifications.
Also check belt routing to make sure there is no interfer-
ence between the belts and other engine components.
Spark Plugs
Spark plugs must fire properly to assure proper engine
performance and emission control. The plugs installed in
your vehicle should operate satisfactorily in normal
service for the mileage indicated in the MaintenanceChart. New plugs should be installed at this mileage. The
entire set should be replaced if there is any malfunction
due to a faulty spark plug. Check the Vehicle Emissions
Control Information label for the proper type of spark
plug for your vehicle.
CAUTION!
When replacing plugs, do not overtighten. You could
damage them and cause them to leak.
Ignition Cables
Replace the ignition cables at the mileage interval shown
in the maintenance charts.
Engine Air Cleaner Filter
Under normal driving conditions, replace the air filter at
the intervals shown on Schedule ªAº. If, however, you
drive the vehicle frequently under dusty or severe con-
ditions, the filter element should be inspected periodi-
cally and replaced if necessary at the intervals shown on
Schedule ªBº.
230 MAINTAINING YOUR VEHICLE
WARNING!
The air cleaner can provide a measure of protection
in the case of engine backfire. Do not remove the air
cleaner unless such removal is necessary for repair or
maintenance. Make sure that no one is near the
engine compartment before starting the vehicle with
the air cleaner removed. Failure to do so can result in
serious personal injury.
Engine Fuel Filter
A plugged fuel filter can cause stalling, limit the speed at
which a vehicle can be driven or cause hard starting.
Should an excessive amount of dirt accumulate in the
fuel tank, frequent filter replacement may be necessary.
Catalytic Converter
The catalytic converter requires the use of unleaded fuel
only. Leaded gasoline will destroy the effectiveness of the
catalyst as an emission control device.Under normal operating conditions, the catalytic con-
verter will not require maintenance. However, it is im-
portant to keep the engine properly tuned to assure
proper catalyst operation and prevent possible catalyst
damage.
CAUTION!
Damage to the catalytic converter can result if your
vehicle is not kept in proper operating condition. In
the event of engine malfunction, particularly involv-
ing engine misfire or other apparent loss of perfor-
mance, have your vehicle serviced promptly. Contin-
ued operation of your vehicle with a severe
malfunction could cause the converter to overheat,
resulting in possible damage to the converter and the
vehicle.
NOTE:Intentional tampering with emissions control
systems can result in civil penalties being assessed
against you.
MAINTAINING YOUR VEHICLE 231
7
WARNING!
Battery posts, terminals, and related accessories con-
tain lead and lead compounds. Always wash hands
after handling the battery.
To determine the battery charge, check the battery test
indicator (if equipped) on top of the battery. Refer to the
illustration.
CAUTION!
It is essential when replacing the cables on the
battery that the positive cable is attached to the
positive post and the negative cable is attached to the
negative post. Battery posts are marked (+) positive
and negative (-) and identified on the battery case.
Also, if a ªfast chargerº is used while battery is in the
vehicle, disconnect both vehicle battery cables be-
fore connecting the charger to battery. Do not use a
ªfast chargerº to provide starting voltage.
Air Conditioner Maintenance
For best possible performance, your air conditioner
should be checked and serviced by an Authorized Dealer
at the start of each warm season. This service should
include cleaning of the condenser fins and a performance
test. Drive belt tension should also be checked at this
time.
MAINTAINING YOUR VEHICLE 233
7
WARNING!
²Use only refrigerants and compressor lubricants
approved by the manufacturer for your air condi-
tioning system. Some unapproved refrigerants are
flammable and can explode, injuring you. Other
unapproved refrigerants or lubricants can cause
the system to fail, requiring costly repairs.
²The air conditioning system contains refrigerant
under high pressure. To avoid risk of personal
injury or damage to the system, adding refrigerant
or any repair requiring lines to be disconnected
should be done by an experienced repairman.
Refrigerant Recovery and Recycling
R-134a Air Conditioning Refrigerant is a hydrofluorocar-
bon (HFC) that is endorsed by the Environmental Pro-
tection Agency and is an ozone-saving product. How-
ever, the manufacturer recommends that air conditioning
service be performed by dealers or other service facilities
using recovery and recycling equipment.
Power Steering Ð Fluid Check
Checking the power steering fluid level at a defined
service interval is not required. The fluid should only be
checked if a leak is suspected, abnormal noises are
apparent, and/or the system is not functioning as antici-
pated. Coordinate inspection efforts through a certified
DaimlerChrysler Dealership.9
WARNING!
Fluid level should be checked on a level surface and
with the engine off to prevent injury from moving
parts and to insure accurate fluid level reading. Do
not overfill. Use only manufacturers recommended
power steering fluid.
If necessary, add fluid to restore to the proper indicated
level. With a clean cloth, wipe any spilled fluid from all
surfaces. Refer to Recommended Fluids, Lubricants, and
Genuine Parts for correct fluid type.
234 MAINTAINING YOUR VEHICLE
The radiator normally remains completely full, so there is
no need to remove the pressure cap except when check-
ing coolant freeze point or when replacing coolant. Your
service attendant should be advised of this. When addi-
tional coolant is needed to maintain the proper level, it
should be added to the overflow bottle. Do not overfill.
Points To Remember
A. Do not overfill the reserve tank (overflow bottle).
B. Check coolant freeze point in the radiator and in the
reserve tank. If antifreeze needs to be added, contents of
reserve tank also must be protected against freezing.
C. If frequent coolant additions are required, or if the
level in the reserve tank does not drop when the engine
cools, the cooling system should be pressure tested for
leaks.D. Maintain a minimum coolant concentration of 50%
ethylene glycol.
E. Make sure that the radiator and reserve tank overflow
hoses are not kinked or obstructed.
F. Keep the front of the radiator clean. If your vehicle is
equipped with air conditioning, keep the front of the
condenser clean also.
G. The thermostat should not be changed for summer or
winter operation. If replacement is ever necessary, install
ONLY the correct type thermostat. Other designs may
result in unsatisfactory cooling performance.
Emission Related Components
Fuel System Hoses And Vapor/Vacuum Harnesses
When the vehicle is serviced for scheduled maintenance,
inspect surface of hoses and nylon tubing for evidence of
heat and mechanical damage. Hard and brittle rubber,
cracking, checking, tears, cuts, abrasions, and excessive
swelling suggest deterioration of the rubber. Particular
attention should be given to examining hose surfaces
nearest to high heat sources, such as the exhaust mani-
fold.
MAINTAINING YOUR VEHICLE 241
7
There are two groups
identified, those for wheel
bearings (Letter ªGº) and
those for chassis (Letter
ªLº) lubrication. Perfor-
mance categories within
these groups result in dual
letter designations for
each group. The letter des-
ignations shown in the ex-
ample are the highest
quality level available and when combined as shown can
be used for chassis lubrication. Use only those greases
that have the NLGI symbol on the container along with
the proper quality level for your application.
Appearance Care and Protection from Corrosion
Protection of Body and Paint from Corrosion
Vehicle body care requirements vary according to geo-
graphic locations and usage. Chemicals that make roads
passable in snow and ice, and those that are sprayed on
trees and road surfaces during other seasons, are highly
corrosive to the metal in your vehicle. Outside parking,which exposes your vehicle to airborne contaminants,
road surfaces on which the vehicle is operated, extreme
hot or cold weather and other extreme conditions will
have an adverse effect on paint, metal trim, and under-
body protection.
The following maintenance recommendations will enable
you to obtain maximum benefit from the corrosion
resistance built into your vehicle.
What Causes Corrosion?
Corrosion is the result of deterioration or removal of
paint and protective coatings from your vehicle.
The most common causes are:
²Road salt, dirt and moisture accumulation.
²Stone and gravel impact.
²Insects, tree sap and tar.
²Salt in the air near seacoast localities.
²Atmospheric fallout/industrial pollutants.
MAINTAINING YOUR VEHICLE 249
7
EMISSION CONTROL SYSTEM MAINTENANCE
The ªScheduledº maintenance services, listed inbold
typeon the following pages must be done at the times or
mileages specified to assure the continued proper func-
tioning of the emission control system. These, and all
other maintenance services included in this manual,
should be done to provide best vehicle performance and
reliability. More frequent maintenance may be needed for
vehicles in severe operating conditions such as dusty
areas and very short trip driving.
Inspection and service also should be done any time a
malfunction is suspected.
NOTE:Maintenance, replacement, or repair of the
emission control devices and systems on your vehicle
may be performed by any automotive repair establish-
ment or individual using any automotive part which has
been certified pursuant to U.S. EPA or, in the State of
California, California Air Resources Board regulations.
EMISSIONS TESTING
In some localities, it may be or will become a legal
requirement to ensure that all emissions components and
systems are functioning properly as a part of the test
procedure. The test center accomplishes this by checking
the On Board Diagnostic System (OBD) system with an
electronic scan tool. If your vehicle has recently been
serviced, the OBD system may have been reset to a9not
ready9condition because the OBD system has not had
sufficient time since the servicing to reconfirm that
emissions components are operating properly. In most
cases, a reasonable mix and amount of normal city and
highway driving and at least one overnight-off period
will be required to prepare your vehicle for this check;
however your dealer has the equipment and procedures
required to make certain that the OBD system of your
vehicle is ready for the required testing.
262 MAINTENANCE SCHEDULES
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