Top 10 Questions for Diesel Mechanic Interview

1. Describe the different types of diesel engines you have worked on and the key differences between them?

• In-line engines: These engines have the cylinders arranged in a straight line, with the crankshaft running through the center. They are typically used in smaller vehicles, such as cars and light trucks.
• V-type engines: These engines have the cylinders arranged in a V-shape, with the crankshaft running through the center. They are typically used in larger vehicles, such as trucks and buses.
• Radial engines: These engines have the cylinders arranged in a circle, with the crankshaft running through the center. They are typically used in aircraft and other applications where space is limited.

2. What are the different types of diesel fuel injection systems?

Mechanical injection systems

• These systems use a mechanical pump to inject fuel into the cylinders. They are typically found in older diesel engines.
• Advantages: Simple and reliable
• Disadvantages: Not as efficient as other systems, can be noisy

Electronic injection systems

• These systems use an electronic control unit (ECU) to inject fuel into the cylinders. They are typically found in newer diesel engines.
• Advantages: More efficient than mechanical systems, quieter, can be programmed to optimize performance
• Disadvantages: More complex and expensive than mechanical systems

3. What are the different types of diesel engine turbochargers?

• Turbochargers increase the power of a diesel engine by compressing the air that is drawn into the cylinders. This allows more air to be burned, which in turn produces more power.
• There are two main types of diesel engine turbochargers: wastegate turbochargers and variable geometry turbochargers.
• Wastegate turbochargers use a wastegate to control the amount of boost pressure that is produced. Variable geometry turbochargers use a set of vanes to control the flow of exhaust gas through the turbocharger, which allows for more precise control of boost pressure.

4. What are the different types of diesel engine emissions control systems?

• Diesel engines produce a number of pollutants, including particulate matter, nitrogen oxides, and hydrocarbons. Emissions control systems are used to reduce the amount of these pollutants that are released into the atmosphere.
• There are a number of different types of diesel engine emissions control systems, including:
  • Exhaust gas recirculation (EGR) systems
  • Diesel particulate filters (DPFs)
  • Selective catalytic reduction (SCR) systems
• These systems work together to reduce the amount of pollutants that are released into the atmosphere.

5. What are the different types of diesel engine cooling systems?

• Diesel engines produce a lot of heat, so it is important to have a cooling system to keep the engine from overheating.
• There are two main types of diesel engine cooling systems: liquid-cooled systems and air-cooled systems.
• Liquid-cooled systems use a coolant to absorb heat from the engine and then transfer it to a radiator, where it is dissipated into the atmosphere.
• Air-cooled systems use a fan to circulate air around the engine and cool it down.

6. What are the different types of diesel engine lubrication systems?

• Diesel engines require lubrication to reduce friction and wear between moving parts.
• There are two main types of diesel engine lubrication systems: wet sump systems and dry sump systems.
• Wet sump systems store the oil in a sump below the engine. The oil is then pumped up to the engine by an oil pump.
• Dry sump systems store the oil in a separate reservoir. The oil is then pumped up to the engine by an oil pump and then returned to the reservoir.

7. What are the different types of diesel engine electrical systems?

• Diesel engines require an electrical system to power the starter, alternator, and other electrical components.
• There are two main types of diesel engine electrical systems: 12-volt systems and 24-volt systems.
• 12-volt systems are typically used in smaller diesel engines, while 24-volt systems are typically used in larger diesel engines.

8. What are the different types of diesel engine fuel systems?

• Diesel engines require a fuel system to deliver fuel to the cylinders.
• There are two main types of diesel engine fuel systems: mechanical fuel systems and electronic fuel systems.
• Mechanical fuel systems use a mechanical pump to deliver fuel to the cylinders.
• Electronic fuel systems use an electronic control unit (ECU) to deliver fuel to the cylinders.

9. What are the different types of diesel engine air intake systems?

• Diesel engines require an air intake system to provide air to the cylinders.
• There are two main types of diesel engine air intake systems: naturally aspirated systems and turbocharged systems.
• Naturally aspirated systems use the natural pressure of the atmosphere to draw air into the cylinders.
• Turbocharged systems use a turbocharger to compress the air before it is drawn into the cylinders.

10. What are the different types of diesel engine exhaust systems?

• Diesel engines require an exhaust system to expel exhaust gasses from the cylinders.
• There are two main types of diesel engine exhaust systems: wet exhaust systems and dry exhaust systems.
• Wet exhaust systems use water to cool the exhaust gasses before they are expelled.
• Dry exhaust systems do not use water to cool the exhaust gasses.

Diesel Mechanics are responsible for maintaining and repairing diesel engines and other mechanical components in a wide range of vehicles and equipment.

1. Diagnose and Repair Diesel Engines

Diagnose and repair diesel engines to identify and resolve problems, using diagnostic equipment and tools.

2. Perform Preventative Maintenance

Perform preventative maintenance on diesel engines and equipment, including oil changes, filter replacements, and inspections.

3. Troubleshoot and Resolve Mechanical Issues

Troubleshoot and resolve mechanical issues with diesel engines and equipment, including fuel injection systems, electrical systems, and hydraulics.

4. Inspect and Repair Diesel Systems

Inspect and repair diesel systems, including fuel tanks, lines, and pumps, to ensure proper operation.

To help you ace your interview for a Diesel Mechanic position, here are some tips and preparation advice.

1. Research the Company

Learn as much as you can about the company you’re interviewing with. Visit their website, read industry news, and check out their social media pages. This will give you a good understanding of their culture, values, and what they’re looking for in a Diesel Mechanic.

2. Practice Your Answers

Take some time to practice answering common interview questions. This will help you feel more confident and prepared during the interview. Some common questions you may be asked include:

• Tell me about your experience as a Diesel Mechanic.
• What are your strengths and weaknesses?
• Why are you interested in working for our company?
• What are your salary expectations?

3. Dress Professionally

First impressions matter, so make sure to dress professionally for your interview. This means wearing clean, pressed clothes that are appropriate for a business setting.

4. Be on Time

Punctuality is important, so make sure to arrive for your interview on time. If you’re running late, be sure to call or email the interviewer to let them know.

5. Be Prepared to Talk About Your Experience

The interviewer will want to know about your experience as a Diesel Mechanic. Be prepared to talk about your skills and qualifications, and how you can contribute to the company.

6. Ask Questions

At the end of the interview, be sure to ask the interviewer any questions you have. This shows that you’re interested in the position and the company.