What Diesel Service Technicians and Mechanics Do

Diesel service technicians and mechanics inspect, repair, or overhaul buses, trucks, and anything else with a diesel engine.

Duties

Diesel service technicians and mechanics typically do the following:

• Follow a checklist of inspection procedures
• Test drive vehicles to diagnose malfunctions
• Read and interpret diagnostic test results, often by using dials, gauges, and other computer equipment
• Raise trucks, buses, and heavy parts or equipment by using hydraulic jacks or hoists
• Inspect brake systems, steering mechanisms, transmissions, engines, and other parts of vehicles
• Do routine maintenance, such as changing oil, checking batteries, and lubricating equipment and parts
• Adjust and align wheels, tighten bolts and screws, and attach system components
• Repair or replace malfunctioning components, parts, and other mechanical or electrical equipment
• Disassemble and reassemble equipment and parts
• Test drive vehicles to ensure that they run smoothly

Because of their efficiency and durability, diesel engines have become the standard in powering our nation’s trucks and buses. Other heavy vehicles and mobile equipment, including bulldozers and cranes, also are powered by diesel engines, as are many commercial boats, passenger vehicles, pickups, and other work trucks. Diesel service technicians who service and repair these engines are commonly known as diesel mechanics.

Diesel mechanics handle many kinds of repairs. They may work on a vehicle’s electrical system, make major engine repairs, or retrofit engines with emission control systems to comply with pollution regulations.

Diesel engine maintenance is becoming increasingly complex as engines and other components use more electronic systems to control their operation. For example, fuel injection and engine timing systems rely heavily on microprocessors to maximize fuel efficiency. In most shops, workers often use hand-held or laptop computers to diagnose problems and adjust engine functions. 

In addition to computerized diagnostic equipment, diesel mechanics use a variety of power and machine tools, such as pneumatic wrenches, lathes, grinding machines, and welding equipment. Handtools, including pliers, wrenches, and screwdrivers, are also commonly used.

Employers typically provide expensive power tools and computerized equipment, but workers generally acquire their own hand tools over time.

For information on technicians and mechanics who work primarily on automobiles, see the profile on automotive service technicians and mechanics.

For information on technicians and mechanics who work primarily on farm equipment, construction vehicles, and rail cars, see the profile on heavy vehicle and mobile equipment service technicians.

For information on technicians and mechanics who primarily work on motorboats, motorcycles, and small all-terrain vehicles, see the profile on small engine mechanics.

Source: Bureau of Labor Statistics, U.S. Department of Labor, Occupational Outlook Handbook, 2012-13 Edition