Service Manuals

Whenever you’re repairing and rebuilding a vehicle’s systems, you must have the service manual for the vehicle on hand. Because each vehicle make and model is slightly different, you’ll often need to look up manufacturer’s information about a particular automotive system. Service manuals contain a variety of helpful information, such as engine identification guidelines, engine specifications, rebuilding specifications, and recommended repair procedures. Service manuals, like tools, are essential to your work. Most auto technicians keep a variety of service manuals on hand for reference, and their collections keep growing all the time.

Note that the term specifications refers to certain precision measurements that are made on certain parts of the vehicle (particularly in the engine). These ideal measurements are determined by the manufacturer and are listed in a vehicle’s service manual. If an engine is to function properly, it must exactly conform to its specifications. Therefore, many engine specifications will need to be checked with precision measuring instruments when you’re doing repairs. You would then compare your measurements to the specifications printed in the service manual, and correct any problems that you found.

Some common engine specifications are the spark plug gap (the width of the gap between the spark plug’s electrodes), the cylinder bore (the inside diameter of the engine’s cylinder), and torque requirements (the specific tightness of fasteners, usually measured in foot-pounds). All of these specifications must be correct in order for an engine to function properly.

Service manuals are available for both engines and entire vehicles. Most service manuals are published by vehicle manufacturers and can be purchased from any dealer or parts supplier. Most manuals are inexpensive, and some cover a wide variety of vehicles and engine models. Some manuals are also published by educational companies. These educational manuals can often be purchased at local bookstores, at an auto parts store, or directly from publishers.

Service manuals are an invaluable resource when you’re doing repairs. Some technicians will attempt to make repairs to a vehicle without using service manuals, but this isn’t a good practice for several reasons.

First, even the most experienced technicians can’t remember every specification for every vehicle make and model. If you work on only one particular make and model all the time, you could probably make many repairs without the use of outside references. However, in most repair shops, technicians work on a large variety of cars made by many different manufacturers. Working without proper reference manuals is like trying to assemble an appliance you just bought without first reading the instructions. You may be able to do it, but it’s not the best method to make sure that the job gets done properly and quickly.

Second, manufacturers may make changes and improvements to their vehicles from year to year. Each year, more and more new vehicles are introduced, and more features are added to existing models. Having a supply of good service manuals will help you to keep up-to-date on the latest changes in the vehicles you service.

Third, manuals are often necessary in those cases where you weren’t the person who took apart a particular component. For example, suppose a customer brings in a vehicle component that he or she took apart and tried to fix. In such a situation, you’ll probably need to refer to a service manual to determine how the part should be reassembled, or even to determine whether certain small parts are missing. With a service manual at hand, you can quickly determine how the component should be assembled and how it should be adjusted once it’s installed.

Service manuals are very useful tools. However, you should realize that manuals can’t tell you everything. Most manuals are written under the assumption that you already know the basics of auto repair— how engines operate, how the various automotive systems operate, how to disassemble and reassemble engines, and how to use the proper tools and measuring instruments required to make repairs. Most service manuals concentrate on specifications for particular vehicle makes and models, such as torque specifications and recommended engine settings. Therefore, service manuals can never take the place of good training. They’re merely supplements that can provide you with specific information about particular vehicles.