Diesel engines usually are heavier and thus usually last longer than gasoline engines. In addition, they use fuel more efficiently than gasoline engines because the higher compression ratios found in diesel engines convert a higher percentage of the fuel into power. Because of their greater durability and efficiency, diesel engines are used to power most of the Nation's heavy vehicles and equipment.
Diesel mechanics repair and maintain diesel engines that power transportation equipment, such as heavy trucks, buses, and locomotives; and construction equipment such as bulldozers, cranes, and road graders. A small number work on diesel-powered automobiles. Diesel mechanics also service a variety of other diesel-powered equipment, such as electric generators and compressors and pumps used in oil well drilling and in irrigation.
Most diesel mechanics work on heavy trucks used in industries such as mining and construction to carry ore and building materials, and by commercial trucking lines for general freight hauling. Most light trucks are gasoline powered, and although some diesel mechanics service gasoline engines, most work primarily on diesel engines.
Mechanics who work for organizations that maintain their own vehicles may spend much time doing preventive maintenance to assure safe operation, prevent wear and damage to parts, and reduce costly breakdowns. During a maintenance check on a truck, for example, they usually follow a regular check list that includes the inspection of brake systems, steering mechanisms, wheel bearings, and other important parts. They usually can repair or adjust a part that is not working properly. Parts that cannot be fixed are replaced. In many shops, mechanics do all kinds of repair work. For example, they may work on a vehicle's electrical system one day and do major engine repair the next. In some large shops, mechanics specialize in one or two types of work. For example, one mechanic may specialize in major engine repair, another in transmission work,another in electrical systems, and yet another in suspension or brake systems.
Diesel mechanics use a variety of tools in their work. They use power tools such as pneumatic wrenches to remove bolts quickly; machine tools such as lathes and grinding machines to rebuild brakes and other parts; welding and flame-cutting equipment to remove and repair exhaust systems and other parts; common handtools such as screwdrivers, pliers, and wrenches to work on small parts and get at hard-to-reach places; and jacks and hoists to lift and move large parts. Diesel mechanics also use a variety of testing equipment. For example, when working on electrical systems, they may use ohmmeters, ammeters, and voltmeters; to locate engine malfunctions, they often use tachometers, dynamometers, and engine analyzers.
For heavy work, such as removing engines and transmissions, two mechanics may work as a team, or a mechanic may be assisted by an apprentice or helper. Mechanics generally get their assignments from shop supervisors or service managers who may check the mechanics' work or assist in diagnosing problems.
Diesel mechanics usually work indoors, although they may occasionally work or make repairs on the road. They are subject to the usual shop hazards such as cuts and bruises. Mechanics handle greasy and dirty parts and may stand or lie in awkward or cramped positions to repair vehicles and equipment. Work areas usually are well lighted, heated, and ventilated, and many employers provide locker rooms and shower facilities.
Diesel mechanics held about 271,000 jobs in 1990. About one-third worked for organizations that owned fleets of trucks, including construction and trucking companies and careeres that haul their own products, such as dairies and bakeries. Others worked for heavy truck dealers, dealers of diesel-powered light trucks and automobiles, truck repair shops, companies that rent or lease trucks, and Federal, State, and local governments. About one-fifth worked for companies that sell and service construction and mining machinery and industrial equipment, such as compressors, pumps, and generators. A small number of diesel mechanics service buses for local transit companies and intercity buslines. Others maintained diesel locomotives for railroads.
Diesel mechanics are employed in every section of the country, but most work in towns and cities where trucking companies, buslines, and other fleet owners have large repair shops.
Training, Other Qualifications, and Advancement
Most diesel mechanics learn their skills on the job. Beginners usually do tasks such as cleaning parts, fueling, lubricating, and driving vehicles in and out of the shop. As beginners gain experience and as vacancies become available, they usually are promoted to mechanics' helpers. In some shops, beginners--especially those having automobile service experience--start as mechanics' helpers.
Most helpers can make minor repairs after a few months' experience and advance to increasingly difficult jobs as they prove their ability. After they master the repair and service of diesel engines, they learn to work on related components such as brakes, transmissions, or electrical systems. Generally, at least 3 to 4 years of on-the-job experience are necessary to qualify as an all-round diesel truck or bus mechanic. Additional training may be necessary for mechanics who wish to specialize in diesel equipment.
For entry jobs, employers generally look for applicants who have mechanical aptitude and are at least 18 years of age and in good physical condition. Completion of high school also is desirable. Good reading skills are needed to study complex service instruction manuals. A State chauffeur's license is needed for test driving trucks or buses on public roads.
Many employers prefer graduates of formal training programs in diesel mechanics. These 1- to 2-year programs, given by vocational and technical schools and community and junior colleges, lead to a certificate of completion or an associate degree. They provide a foundation in the basics of the latest diesel technology, such as the use of electronics, and speed advancement to the journey-man mechanic level.
A formal 4-year apprenticeship is another good way to learn diesel mechanics. While never plentiful, apprenticeships are becoming rare because employers are reluctant to make such a long-term investment in training, especially when graduates of postsecondary diesel mechanic programs are increasing in number. Typical apprenticeship programs for diesel truck and bus mechanics consist of approximately 8,000 hours of practical experience working on transmission, engines, and other components and at least 576 hours of formal instruction to learn blueprint reading, mathematics, engine theory, and safety. Frequently, these programs include training in both diesel and gasoline engine repair.
High school auto shop and science and mathematics classes help a mechanic understand how engines and vehicles operate. Practical experience in automobile repair in a gasoline service station or the Armed Forces or from a hobby also is valuable. Most mechanics must buy their own handtools. Experienced mechanics often have thousands of dollars invested in tools.
Employers sometimes send experienced mechanics to special training classes conducted by truck, bus, diesel engine, parts, and equipment manufacturers where they learn the latest technology or receive special training in subjects such as diagnosing engine malfunctions. Mechanics also must read service and repair manuals to keep abreast of engineering changes.
Voluntary certification by the National Institute for Automotive Service Excellence is recognized as a standard of achievement for diesel mechanics. Mechanics may be certified as Master Heavy-Duty Truck Technicians or may be certified in 1 or more of 6 different areas of heavy duty truck repair: Brakes, gasoline engines, diesel engines, drive trains, electrical systems, and suspension and steering. For certification in each area, mechanics must pass a written examination and have at least 2 years of experience. High school, vocational or trade school, or community or junior college training in gasoline or diesel engine repair may substitute for up to 1 year of experience. To retain certification, mechanics must retake the tests at least every 5 years.
Experienced mechanics who have leadership ability may advance to shop supervisors or service managers. Mechanics who have sales ability sometimes become sales representatives. A few mechanics open their own repair shops.
Employment of diesel mechanics is expected to increase about as fast as average for all occupations through the year 2000 as freight transportation by trucks increases. More trucks will be needed for both local and intercity hauling due to the increased production of goods. Additional diesel mechanics will be needed to repair and maintain growing numbers of buses and heavy construction graders, cranes, earthmovers, and other equipment. Due to the greater durability and economy of the diesel relative to the gasoline engine, buses and trucks of all sizes are expected to be increasingly powered by diesels, also creating new diesel mechanic jobs. The majority of job openings, nevertheless, will arise from the need to replace diesel mechanics who transfer to other occupations, retire, or stop working for other reasons.
Careers in diesel mechanics are attractive to many because wages are relatively high and skilled repair work is challenging and varied. Opportunities will be best for persons who complete formal training in diesel mechanics at community and junior colleges and vocational and technical schools.
Diesel mechanics employed by trucking companies, buslines, and other firms that maintain their own vehicles had average hourly earnings of $13.88 in 1990. Earnings generally were highest in the West and North Central regions and lowest in the South. They varied by industry as follows:
Retail trade....................... 13.42
Wholesale Trade.................... 14.05
Beginning apprentices usually earn from 50 to 75 percent of the rate of skilled workers and receive increases about every 6 months until they complete their apprenticeship and reach the rate of skilled mechanics.
Most mechanics work between 40 and 48 hours per week. Those employed by truck and bus firms which provide service around the clock may work evenings, nights, and weekends. They usually receive a higher rate of pay for this work.
Many diesel mechanics are members of labor unions, including the International Association of Machinists and Aerospace Workers; the Amalgamated Transit Union; the International Union, United Automobile, Aerospace and Agricultural Implement Workers of America; the Transport Workers Union of America; the Sheet Metal Workers' International Association; and the International Brotherhood of Teamsters, Chauffeurs, Warehousemen and Helpers of America (Ind.).
Diesel mechanics repair trucks, buses, and other diesel-powered equipment and keep them in good working order. Related mechanic occupations include aircraft mechanics, automotive and motorcycle mechanics, farm equipment mechanics, and mobile heavy equipment mechanics.
Sources of Additional Information
More details about work opportunities for diesel mechanics may be obtained from local employers such as trucking companies, truck dealers, or bus lines; locals of the unions previously mentioned; or the local office of the State employment service. Local State employment service offices also may have information about apprenticeships and other training programs.
For general information about careers as truck, bus, and diesel mechanics write to: American Trucking Associations, Inc., 2200 Mill Rd., Alexandria, VA 22314.
Automotive Service Industry Association, 444 North Michigan Ave., Chicago, Ill. 60611.
International Association of Machinists and Aerospace Workers, Apprenticeship Department, 1300 Connecticut Ave. NW., Washington, D.C. 20036.
Motor Vehicle Manufacturers Association of the U.S. Inc., 300 New Center Bldg., Detroit, Mich. 48202.
Information on diesel mechanic training is available from:
Motor and Equipment Manufacturers Association, Technical Training Council, 222 Cedar Lane, Teaneck, N.J. 07666.
For a directory of accredited private trade and technical schools with training programs for diesel mechanics, contact:
National Association of Trade and Technical Schools, 2251 Wisconsin Ave., NW., Washington, D.C. 20007. Information on how to become a certified heavy-duty diesel mechanic is available from:
National Institute for Automotive Service Excellence, 1825 K St., NW., Washington, D.C. 20006.