Career roadmap
How to Become a Diesel Mechanic
The education, training, certifications and steps it takes to start working as a diesel mechanic, plus how long it takes and where the career can lead.
To become a diesel mechanic: (1) finish high school, (2) complete diesel technology training, (3) start as an entry-level tech, (4) earn ASE certifications, (5) specialize. Most people need about 6–24 months. BLS lists “high school diploma or equivalent” as the typical entry-level education.
5 steps to become a diesel mechanic
Finish high school
Auto shop, math and electronics are useful.
Complete diesel technology training
A technical program teaches engines, electrical, brakes and diagnostics.
Start as an entry-level tech
Lube tech or apprentice roles build experience.
Earn ASE certifications
Pass T-series tests after meeting experience requirements.
Specialize
Become a diagnostics specialist, field service tech, shop lead or fleet manager.
Education and training requirements
A high school diploma is typical. Many diesel techs complete a six-month to two-year program at a technical school or community college; others start as lube techs and learn on the job.
| Typical entry-level education (BLS) | High school diploma or equivalent |
|---|---|
| Related work experience | None |
| On-the-job training | Long-term on-the-job training |
| Typical training time | 6–24 months |
Certifications and licenses
- ASE Medium-Heavy Truck (T-series): Certifications covering diesel engines, drivetrains, brakes, suspension, electrical and more.
- DOT annual inspector qualification: Required to perform federal periodic inspections on commercial vehicles.
- Manufacturer certifications: Training from engine and truck makers such as Cummins, Detroit or Freightliner.
- CDL: Helpful for road-testing and moving trucks.
Skills to build now
Start with diesel engine diagnostics, air brake systems, and electrical and electronic troubleshooting, and practice problem-solving and attention to detail. Learning the diesel mechanic vocabulary early makes training and interviews easier.
Where the career can lead
- Lube Tech or Apprentice: Perform services and learn systems.
- Diesel Technician: Diagnose and repair trucks and equipment.
- Master or Lead Technician: Handle complex diagnostics and mentor others.
- Shop Foreman or Fleet Manager: Run maintenance operations.
Get a head start
Our self-paced Diesel Mechanic training gives you a realistic, practical overview of the job (duties, terminology, step-by-step tasks, safety and interview prep) so you can decide with confidence and show employers you’re serious.
Common questions about getting started
How long does it take to become a diesel mechanic?
Technical programs take six months to two years. Many techs also learn on the job and earn ASE certifications after gaining experience.
Do diesel mechanics need certification?
Not legally in most cases, but ASE certifications and manufacturer training raise pay and opportunities.
How long does it take to become a diesel mechanic?
Most people need about 6–24 months of training. A high school diploma is typical. Many diesel techs complete a six-month to two-year program at a technical school or community college; others start as lube techs and learn on the job.
Do you need a degree to be a diesel mechanic?
No four-year degree is typically required. BLS lists “high school diploma or equivalent” as the typical entry-level education, plus long-term on-the-job training.
Sources
- U.S. Bureau of Labor Statistics, BLS Occupational Employment and Wage Statistics (OEWS), May 2025, SOC 49-3031 (Bus and truck mechanics and diesel engine specialists).
- U.S. Bureau of Labor Statistics, BLS Employment Projections, Table 1.2 (2025–35).
- O*NET OnLine summary for Bus and truck mechanics and diesel engine specialists (U.S. Department of Labor).
- BLS Occupational Outlook Handbook.
Reviewed by the Career Education Institute Curriculum Team. Pay figures are national estimates; local pay varies. See our editorial policy.