Popular Schools

The listings below may include sponsored content but are popular choices among our users. x
Penn-Foster responds quickly to information requests through this website.


Penn-Foster responds quickly to information requests through this website.
Penn Foster High School responds quickly to information requests through this website.

Penn Foster High School

High School Diploma
Penn Foster High School responds quickly to information requests through this website.

Online Diesel Mechanics Programs

Learn about online diesel mechanics programs, including how they're delivered, what you'll learn, and how to become a certified diesel mechanic. Additionally, discover what the job of a diesel mechanic is like.

An Overview of Online Diesel Mechanics Programs

Diesel mechanics must be skilled in vehicle repair and the maintenance for diesel engines. Diesel engines differ from regular automobile engines and are commonly used in larger vehicles such as trucks, buses, and some construction equipment. Due to the nature of the field, hands-on training can be very important to learning the material in a diesel technology program, and because of this, many of these programs are only offered in person. However, there are several distance education options for those who wish to learn the material online.

Types of Online Diesel Mechanics Programs

There are two main types of online diesel mechanics programs: those offered through a post-secondary institution, and those offered through a professional organization that is specific to the auto industry, usually for independent study. Each type of program can prepare students to take the National Institute for Automotive Service Excellence (ASE) certification tests.

Post-secondary Programs

Online diesel mechanics programs that are offered through an accredited post-secondary institution are typically a bit more structured than other types of programs. While the learning is still self-paced, there are individual courses for the topics in the program, and students may be given tests and exams for each course. Students may receive course materials such as textbooks. Depending on the program, students can reach out to staff members for any questions about the material or learning format. Upon graduation, students may be given a career diploma or certificate.

Independent Study Programs

Online diesel mechanics programs that are not affiliated with any post-secondary institution are commonly offered through the websites of professional organizations related to the automobile and diesel truck industries. These websites typically deliver the learning topics through instructional videos and other visual aides that can be studied entirely at one's own pace. Sometimes they may be broken up into courses like post-secondary programs, but this can vary. Once students complete the program, a diploma or certificate isn't usually granted.

How Long Do Online Diesel Mechanics Programs Last?

The length a program lasts depends on what institution is offering it. While many programs are intended for students to learn at their own pace, they may place an expiration date on the program. For example, if a student does not complete the program within one year, they may have to re-enroll. Other programs state they can be completed in as few as 4-7 months. Some programs, such as those where you download a video or study guide, will have no expiration at all.

Practical Requirements for Online Diesel Mechanics Programs

Studying diesel engines online may not require hands-on training, but it is beneficial if you want to apply the skills you're learning. On-campus programs usually require students to attend lab sessions in order to gain practical skills. Online students typically don't have this same access. However, you can try practicing on a diesel vehicle of your own or borrow one if possible.


Diesel mechanics use large power tools along with smaller mechanical tools to perform their work. The smaller tools are usually owned by the mechanic as part of their personal set while the larger power tools are supplied by the shop. Consider building your own collection of small tools to practice with as you study.

Are There Any Prerequisites for Online Diesel Mechanics Programs?

There typically aren't any prerequisites for online diesel mechanics programs. Most of the time, enrolling is as simple as signing up and paying a registration fee. While it may not explicitly be required, waiting until you are at least 18 years old, have graduated from high school or earned your GED, and can legally drive before signing up can be a good idea.

Common Courses in Online Diesel Mechanics Programs

Most online diesel mechanics programs will have text documents and instructional videos for students to learn from. Sometimes the material will come through only one of those mediums. Other programs may send students a textbook to study from in addition to what is provided online. Depending on the program, topics may be broken up into separate courses or each topic will get its own video or study guide.

Diesel Mechanics/Heavy Truck Maintenance Introduction

This is one of the first classes students may take. As an introductory course, it serves as an overview of the diesel industry. Students can learn about the different jobs in the diesel repair field and about the basic operations of diesel engines.


Courses about heavy truck drivetrains cover the driveline system, including drive axles, clutches, and automatic and manual transmissions. Students can learn about how these systems work, their components, and how to maintain and repair them.

Safety, Operation, and Technology

Students in this course can learn in more detail about how diesel engines operate, including why they're a common choice for powering heavier vehicles. Other topics can include what the typical safety protocols are in repair shops and the different tools that are used for diesel maintenance and repair.

Fundamentals of Diesel Engines

Courses about the fundamentals of diesel engines look at diesel engines as a whole and as components. Students can learn about the different parts that make up diesel engines and how they function. A few points students may learn about are crankshafts, engine blocks, and piston assemblies as well as cylinder heads and camshafts.

Truck Electrical Systems

Courses about the electrical systems of trucks cover basic electrical topics and functions of a truck's electrical systems. Students may start with learning about electrical theory before continuing on to electrical systems. A few topics can include system monitoring programs, battery types, lighting, wiring, and starting and charging systems.

Truck Fuel Systems

Courses about truck fuel systems cover the function of fuel and injection systems of various types of trucks. Students can learn about the various components of these systems and how to perform maintenance tasks on them.

HVAC Systems for Heavy Trucks

Courses about HVAC systems cover the heating, air-conditioning, and ventilation systems of heavy truck vehicles. Students can learn about the different components of these systems, how they work separately as well as together, and how to maintain them. Other topics covered can include the control systems for truck HVACs, auxiliary power units (APUs), and how auxiliary power units work alongside HVAC systems.

Diesel Mechanic Job Options

Once you've completed a diesel mechanics training program, you may begin pursuing work in the industry. According to the U.S. Bureau of Labor Statistics, the annual median pay in 2019 for diesel service technicians and mechanics was $48,500. From 2018-2028, the profession is expected to grow by 5%.

What Does a Diesel Mechanic Do?

Diesel mechanics, also known as diesel technicians, work with large vehicles such as buses, trucks, and construction equipment that use diesel engines. While the type of engine they work with may set them apart from traditional automobile mechanics, they still work with all parts of a large vehicle, not just the engine.

Diesel mechanics typically work in repair shops to perform maintenance and repair tasks. The shops they work in are well-ventilated to protect them from harmful fumes and well-lit to ensure they have enough light to work safely and properly. Due to the nature of their work, they often have to sit or lie in uncomfortable positions in order to reach the part of a vehicle they need to. This also usually requires physical strength and stamina. They use a mix of equipment, such as grinding machines and welding equipment, and smaller handheld tools such as pliers and screwdrivers. Before they use any tools though, diesel mechanics use electronic equipment to diagnose problems first.

A few specific tasks that diesel mechanics usually perform can include:

  • Changing oil and tires; checking fluid levels
  • Ensuring engines meet pollution regulations
  • Inspecting one or all systems of a vehicle, such as the brakes or steering
  • Performing diagnostic tests and interpreting results to determine what needs to be done
  • Consulting with clients about their vehicle's diagnosis and repairs

What are the Education and Training Requirements?

Diesel mechanics typically don't need any formal education beyond a high school diploma or GED. They usually train on the job. However, it is becoming more common for employers to look for or require diesel mechanics to complete a postsecondary diesel technology program.

For those without postsecondary education or hands-on instruction, an employer may require new diesel mechanics to train for a longer period of time under the supervision of an experienced diesel mechanic. Training may start out with the new mechanic working on basic tasks, such as driving vehicles around the shop, checking fluid levels, and cleaning parts. Once a trainee demonstrates competence with basic maintenance and repair tasks, they may learn more complicated tasks.

Complete training for a new diesel mechanic can take 3 to 4 years. New hires aren't the only ones who have to go through training, however. Since diesel technology is constantly developing, experienced mechanics may need to continuously take classes to learn about the latest technology and equipment.

Required Skills for Diesel Mechanics

The field of diesel technology requires mechanics to have strong skills in certain areas. These skills can include:

  • Mechanical knowledge: Diesel mechanics must know how several components and systems function, as well as how to take them apart and put them back together.
  • Detail-oriented: When performing inspections and repairs, diesel mechanics must be able to spot the smallest of details. This is usually because electronic and mechanical problems are commonly caused by issues that can be easy to miss.
  • Customer-service abilities: Diesel mechanics work with customers to identify and inform them of their vehicle's problems and what they can do to fix it. They need to be good listeners and ready to answer any questions customers may have.
  • Dexterity: Due to their use of tools and taking apart engines and other components, diesel mechanics need good hand-eye coordination and a steady hand.
  • Troubleshooting understanding: Electronic equipment is often used to diagnose and fix problems, so diesel mechanics need to be able to operate this equipment as well as understand how it functions.
  • Organization: In order to work safely and effectively, diesel mechanics need to keep the spaces they work in organized and clean, especially since they work with a lot of different tools and parts.

Professional Certifications for Diesel Mechanics

The National Institute for Automotive Service Excellence (ASE) offers certification for diesel mechanics. Becoming certified can demonstrate a mechanic's competence and knowledge, especially to clients and employers. Although certification is not usually required, it can advance one's chances of getting hired and may give them a higher salary.

To become certified, diesel mechanics must pass a test. They will also need a certain amount of work experience, education, or a combination of both; the amount varies with each test. Certification for diesel mechanics can be earned in several different areas, all of which are part of the ASE's medium and heavy-truck certification test series. These areas include:

  • Diesel Engines
  • Gasoline Engines
  • Brakes
  • Drivetrain
  • Suspension and Steering
  • Heating, Ventilation, and Air Conditioning
  • Electrical/Electronic Systems
  • Preventative Maintenance Inspection

For more experienced mechanics, there is another certification option, known as the Electronic Diesel Engine Diagnosis Specialist certification. It is for mechanics who can diagnose advanced issues with diesel engines in medium and heavy-duty trucks. The test covers several diesel engine components, such as electronic controls, fuel and exhaust systems, and electric and hydraulic injection systems. To qualify for the test, mechanics must have passed at least one diesel engine test and one electrical/electronic systems test.

Master certification can also be obtained by those who have passed a particular set of tests.

No matter how many certifications they may have, diesel mechanics must pass a recertification exam every 5 years to keep their certification.