Top 18 Auto Mechanic Interview Questions & Answers (2021)

1)      Explain how you can keep your car in good condition?

Regular check-up of parts  like

  • Check battery
  • Tyres and brakes
  • Fluid levels ( Coolant, Washer fluid, Brake fluid, Oil, Power steering, etc.)
  • Fuel filters and Injectors
  • Belts and hoses
  • Alternator
  • Lubrication of wheel
  • Bearing and ball joints

2)      How often does a car requires services?

Car requires services yearly and major maintenance at 6,000 miles.

3)      Before buying a used car what things you should look for?

  • Any leakage of oil underneath the car
  • Check any leakage of coolant water from the radiator
  • Check battery condition
  • Check whether car emits blue gray, dense smoke or a normal smoke from exhaust pipe
  • Watch out for engine noises, any vibrations, lack of power or any other issues
  • Check for any burning smells when open the hood
  • Check steering wheel, driver’s seat and inner door
  • Check tyres ( Edge should not worn out, no bulge on the sidewall, no cuts, enough groves to hold the road)
  • Check all meter work fine when you start the car

Auto Mechanic

4)      Explain how timing belt works?

Timing belt rests on the crankshaft pulley and either one or two camshaft pulley; they are all align through timing belt. The closing and opening of engine valves are controlled by camshaft to let in air and fuel mixture or exhaust gas, if you do not have a timing belt or damaged timing,  it will directly affect the timing of opening and closing of engine valves. This is the reason it is called timing belt and if not in a good position, it will damage your engine.

5)      Explain what is the difference between Crankshaft and Camshaft?

  • Crankshaft: It is linked to the pistons by the connecting rods, the force produced by the fuel-air mixture is transmitted to the crankshaft and converted to rotary motion as the crankshaft turns.
  • Camshaft:  It controls the intake and exhaust valves. It is linked with crankshaft either by timing chain or belt, and it turns one rotation for each two rotations of the crankshaft, for each valve it operates- the cam opens each valve at the correct time to draw fuel and air mixture or expel the exhaust gas


 6)      What may cause  engine overheat?

Engine gets overheat when

  • Coolant leaks
  • Cooling system clogged
  • Weak radiator cap
  • Thermostat stuck shut
  • Inoperative electric cooling fan
  • Bad fan clutch, slipping fan belt, missing fan shroud
  • Too high or low concentration of anti-freeze
  • Collapsed radiator hose or debris in the radiator
  • Restricted exhaust system

7)      What is automotive charging system is made up of?

Automotive charging system is made up of

  • Battery
  • Voltage Regulator
  • Alternator

8)      What is the standard reading in voltmeter for functional battery?

For functional battery, the standard reading for voltmeter is 14-15 which is normal, but if reading shows 13 or less then, there is a problem with the battery.

9)      How can you judge whether the problem is due to alternator and not due to battery?

To judge the problem for an alternator, there are few steps you can try

  • Run your car and unplug the positive connection of the battery, if the car stops then it is more likely there is a problem with the alternator
  • Another way of checking alternator is by checking interior lights, usually an alternator charges your car battery when the car is on.  If the interior lights come on brightly and fades away slowly, it indicates that the alternator cannot keep a charge when the car is running.  It means there is a problem with the alternator.
  • You can also check by racing your car with headlights on, if the light brighten up when you race the car and lose power when you slow it down, indicates a problem with the alternator

10)   Explain what are the components in alternator and how it works?

An alternator consists of the stator, rotor and copper wiring. The rotor and stator are belt driven magnets encased in copper wiring, which creates a magnetic field.  This belt is connected with engine, so when engine starts it rotates the rotor and generate a magnetic field. Stator converts this magnetic field into voltage that flows to the diode.  The diode assembly converts the AC electricity to DC, which is used by car battery.

11)   What are the important components of Engine lubrication system?

Important components of engine lubrication system includes

  • Oil pan: It is a container where engine oil settles down when car is not running
  • Pickup tube: When engine starts oil get sucked up through pickup tube
  • Oil pump: The pump will help to slide up oil into the tube against the gravity
  • Pressure relief valve: It relieves the pressure on oil
  • Oil filter: It removes dirt and debris form the oil
  • Spurt holes and galleries: These are the holes in the crankshaft or other parts of the engine through which oil streams and make them lubricated
  • Sump: Once it has lubrication job is done it will go back again into oil pan or sump

12)   Explain what is kingpin offset?

Kingpin offset the part, which is usually used as a pivot in the vehicles steering.

13)   What do you mean by CC when mentioning car efficiency?

CC stands for Cubic Centimetres; it tells the total volume of the engine cylinder.  It indicates that the automobile with more CC produces more power than the other engines.

14)   How petrol engine is different than diesel engine?

  • Petrol engine: Petrol engine works on the principle of Intake (fuel + air), Compression, Power and Exhaust. It means the fuel, and air will enter the combustion chamber, piston come upwards and compress the fuel. The compressed fuel comes in contact with spark plug and produces a spark that push piston down
  •  Diesel Engine:  In diesel engine the phenomenon is slightly different, there is no sparkplug in diesel engine. In here only air enters in the burning chamber, when piston is pushed up by motor, it will compress the air in the chamber, making it hot.  Now valve opens and inject diesel, because of compressed air, the diesel blasts and push the piston down


15)   Explain clutch system works?

Clutch system is made up of two metal plates adjacent to the engine.  When you press the clutch pedal down the plates come apart separating the engine from the drive wheels allowing the drivers to change the gear, and re-engage the plates again with the engine once the gear is changed

16)   Explain what is the benefit of dual clutch transmission?

The dual clutch transmission allows gears to be pre-selected before they are changed, so one clutch selects the second gear while the second clutch selects the third gear.  There are usually seen in race cars

17)   Explain what do you mean by independent suspension?

Independent suspension is referred to the mounting of the wheel on a separate axle.  So, that road shocks affect only the particular wheel.

18)   Mention the injector pressure in heavy vehicle?

Injector pressure in heavy vehicle is about 220 kg/cm square.


  1. Is there a water powered car in today’s technology

    1. if not i’m sure we can make it happen

  2. Good explanation of topics of Iti M/D

  3. Dada Jacob Kenyi says:

    Why some time vehicle keeping over heating when check every things are fine

    1. Gasket will be not fine or thermostat value will be not a fine

    2. There are many reasons. coolant level low or radiator inside air

  4. Desalegn Mark says:

    Good info thanks alot.

  5. The content was really helpful. Thanks

  6. It really help me … Thanks

  7. HERAMAN harrylall says:

    I have a 2002 year model Toyota allion an it’s burning plenty gas I change the maf sensor the oxygen sensor the injector the exhaust system the computer box an it’s still burning plenty gas

    1. Your spark plugs are responsible for sparking combustion in your engine.
      If they misfire, or are working poorly, this can affect your gas mileage in a negative way.
      Having bad fuel injectors can cause bad mileage.
      Having your air conditioner on causes a lot of gas to be wasted in powering the system.

  8. Rajesh singh says:

    Its really healpfull 4 me… Thnkzzz a lots

  9. Waheed Khan says:

    Nice questions it is very help ful for technicians

  10. Azanfayaz says:


    Can any auto Machnic remove Trc sensor and joint wire to abs or other parts? Light wil be show or not in Toyata vitz car

  11. K HEMA HARISH says:

    It is very useful

  12. weddie Grant says:

    Much helpful
    N realy tax wish u add mo off it
    Ur helpn upcomin automobile technician
    Kip it up

  13. Glenn Hancock says:

    have 2017 Nissan Qashqai need to now were and how to change cabin filter . tks Glenn

    1. Open your glovebox and empty it out completely then locate pin on the outside edge. Use your screwdriver to take the screw out then slip the pin out of the hole on arm.

  14. Nabaasa Rabecca says:

    Thanks alot
    God Bless you

  15. Nguan Bol Riek says:

    Thanks for questioner and answers

  16. Trae H Swann says:

    I have a 93 Cummins 5.9 in my RV. It has an exhaust brake. Is there any reason why I can’t install a similar device on the intake so it will engine brake like a gas engine vehicle?

  17. This is information is quite detailed and easy to refresh one day to the interview date. Thank you.

  18. Courage Chifamba says:

    This is really helpful, thank you!

  19. Dev kimar says:

    Good automobile knowledge

  20. Hi, I have a 2019 Subaru Impreza, it broke down on me last week, took it to the dealership since it’s still under warranty, at first they thought faulty fuel pump, then a week goes by they fold me it was bad gas or e85 was put in it, not sure if they said that because I’m a girl but I know 87 or non ethanol only in my cars, I may not drive much but enough to get gas to keep flowing in my car, my boyfriend drives less and fills his truck with cheaper gas than I do at a reservation and has had this vehicle a lot longer, my car has 3,500 miles only and they made me pay $440 for them to drop the gas tank and clean fuel injectors, the night it broke down it ran fine but randomly stalled out, it had ran fine starting each and everyday, it was halfway through the gas already before it randomly stalled out up a hill nonetheless so it could’ve been everything, just found it weird they would assume it was bad gas or e85 put in it when I alwaya go to Sam’s club and they don’t even sell e85 gas.

    1. Due to its hydroscopic nature, E85 attracts moisture from the air. The end result is a buildup of water in the fuel system. This water can cause damage to injectors, pumps, lines and regulators, if not properly addressed.
      It can also damage rubber seals, gaskets, and other non-metallic components. … A car running on E85 has about 80% the efficiency of the same car running on gasoline.

  21. Hey can u help me find where the engine control module is located on a 1998 Lincoln Navigator? Maybe a link to a video on how to remove it would be very helpful thanks.

  22. Bwambale maani says:

    Good and educative information.

  23. Diane Ruhmshottel says:

    Does it cost to. Askquestions?

  24. Kirti rathod says:

    Your questions are helpful. Post more Questions on Gear box, Brake, Wheel systems -their maintenance and causes of frequent failures

  25. is there motor power car

  26. we have AT 2.03T vehicle. on the gear running 4×2 or 4×4 , there is no problem. but when you stop car on 4×4 ,the car completely viburating. only the issue in idle on 4×4 gear.there is DTC U010008 & U010108.

  27. Francis komla Gablah says:

    i would like to learn more
    thank you.

  28. DARSHANKUMAR S L says:

    Good questions

  29. DARSHANKUMAR S L says:

    Good questions and answers

  30. Gaurav kumar says:

    I liked and learnt.

  31. Otang'o were says:

    Very educative.

  32. Amrit lal says:

    Thanks so much for all the questions and answers.I hope I get to learn more and learn hands on experience in automotive

  33. Wesley Sinyangwe says:

    Great questions, thanks alot

  34. Good explanation Thanks

  35. Dennis kihara says:

    Really learnt alot

  36. Ajang Mayon kur says:

    Good questions and answers
    I need more

  37. Innocent wisiky says:

    So helped,I am happy cause off online helped

  38. Overall nice quetions.

  39. my car front car rear 2 tyre very bad.put new tyre front or rear which one better?

  40. This information is awesome.Between the petrol engine and diesel engine which one is more advantageous than the other?

  41. #8 should be more specific. Static operating voltage on a 12V battery is ~12.6V. *NOT* 13V-14V.
    If the engine is running and the alternator is operating optimally THEN it should be in the ~13.7 – 14.7V range.

  42. Learned alot. Thanks

  43. James Chilumbu jr says:

    Nice send more

  44. johnkamunda says:

    I liked the questions

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