This supplemental Service Manual contains diagnosis, on-vehicle service, wiring diagrams, and component unit repair for Medium Duty Steel Cab Vehicles. (NPR / NPR HD / NQR W3500 / W4500 / W5500 DIESEL ENGINE). When used with the Service Manuals (Pub. No. NPD01-WSM-C01 and NPD02-WSM-CS1 for chassis and NPD01-ESM-C02 for Engine), complete service coverage is provided. Keep this manual in a handy place for ready reference. If properly used, it will enable the technician to serve the owners of these vehicles.
This service manual is intended for use by professional, qualified technicians. Attempting repairs or service without the appropriate training, tools, and equipment could cause injury to you or others and damage to your vehicle that may cause it not to operate properly.
These vehicles contain parts dimensioned in the metric system as well as in the customary system. Some fasteners are metric and are very close in dimension to familiar customary fasteners in the inch system. It is important to note that, during any vehicle maintenance procedures, replacement fasteners must have the same measurements and strength as those removed, whether metric or customary. (Numbers on the heads of metric bolts and on surfaces of metric nuts indicate their strength. Customary bolts use radial lines for this purpose, while most customary nuts do not have strength markings.) Mismatched or incorrect fasteners can result in vehicle damage or malfunction, or possibly personal injury. Therefore, fasteners removed from the vehicle should be saved for re-use in the same location whenever possible. Where the fasteners are not satisfactory for re-use, care should be taken to select a replacement that matches the original. For information and assistance, see your authorized dealer.
Isuzu Commercial Truck Service Manual
Proper service and repair are important to the safety of the service technician and the safe, reliable operation of all motor vehicles. If a part replacement is necessary, the part must be replaced with one of the same part number or with a part of the same quality. Do not use an incorrect or a replacement part of lesser quality. The service procedures recommended and described in this service manual are effective methods of performing service and repair. Some of these procedures require the use of tools specially designed for the purpose.
VIN (VEHICLE IDENTIFICATION NUMBER) AND WEIGHT RATING PLATE
The VlN and Weight Rating Plate (figure 4) lists the manufacturer, gross vehicle weight for the vehicle, maximum front end weight at ground, maximum rear end weight at ground, and the VlN (vehicle identification number). This plate is attached to the inner face of the cab side panel on the driver side.
The vehicle identification number is a legal identifier of your vehicle. It not only appears on the VlN plate, but also on the Vehicle Certificates of Title and Registration. The vehicle identification number specifically identifies a vehicle by code. Figure 5 displays the codes and descriptions for the model covered in this manual.
SERVICE PARTS IDENTIFICATION LABEL
The “Service Parts Identification” label (figure 6) lists major components and their part numbers plus vehicle options and their codes. The information on the label was printed at the factory; therefore, it represents only the equipment on the vehicle when it was shipped from the factory. Always refer to this label when ordering replacement service parts. (Refer to the “NOTICE” on the label.) The service parts identification label is attached to the inner face of the cab side panel on the Passenger side.
ENGINE OIL AND VISCOSITY RECOMMENDATIONS
The oil industry markets various types of engine oil under certain service designation and specification numbers. The selection of a reliable supplier and close attention to the oil and filter element change recommendations can provide satisfactory lubrication and longer life for the engine. Using the proper engine oil and following the recommended oil change intervals is your best assurance of continued reliability and performance from your vehicle’s engine. Engine oil containers are labeled with various APl(American Petroleum Institute) designations of quality. Be sure the oil you use has the API designation “CD”, either alone or shown with other designations such as “SF/CD”. Oils which are not labeled “CD” should not be used.