Basic Vehicle Parts Under Your Hood and What They Do

What Is All This Stuff Under the Hood?

When you receive regular maintenance on your car, like oil changes and tire rotations, most mechanics also perform a multi-point inspection. And most likely, you trust them to tell you if something needs replacing or anything is wrong with those weird boxes, wires, and tubes under the hood.

In case of a roadside emergency—or to simply better recognize the ways auto parts work together—it’s beneficial to be equipped with some basic knowledge the next time you take a peek under the hood of your car. Whether you’re an aspiring DIY mechanic or you recoil at the thought of operating on your vehicle’s metal organs, browse this beginner’s guide to car parts from Kennedy Transmission.


Let’s start with one we hope you know. It’s that hunk of metal that puts the “mobile” in “automobile” and keeps its wheels turning—the heart of the car, if you will. The engine is the biggest apparatus that is generally in the center of everything else. For more information about your specific engine, your car’s user manual is a fantastic resource.


If your car won’t start, it’s important to determine if it’s an issue with the battery or alternator. Alternators look like a wheel with slits with turning gears on the side, and they produce electrical power that recharges the battery and keeps the engine running.


Depending where yours is located within the engine compartment or if there is a protective panel covering it, the battery is pretty easy to spot (often in a corner). It’s a rectangular box with two different-colored terminals on each side: red for positive, black for negative.


Belts help manage different engine operations like alternators, air conditioners, and pumps. Many newer car models have a single serpentine belt that wraps around the engine’s pulleys; one side is flat while the other features several ribs.

Cylinders and Spark Plug Wires

Engines can contain varying amounts of cylinders, which are units that transform gasoline into power. Four, six, or eight cylinders power most modern vehicles, but there are also cars with more or fewer. Usually, each cylinder has its own spark plug—which assists the ignition system—attached to wires.

Piston and Crankshaft

Pistons are housed in the cylinders, are adjacent to each other on the crankshaft, and move upward and downward to create movement in the crankshaft. The crankshaft generates rotational energy so your wheels can propel the vehicle forward.

Oil Fill Cap and Dipstick

If you change your own engine oil, this is where it’s changed and refilled. The fill cap is located on top of the engine and may be labeled “oil fill,” “engine oil,” or with an oil can icon. There will also be a dipstick for checking the oil levels, which should sit in between the min and max marks.


The radiator is a heat exchanger used for cooling and regulating engine temperature. It is the large panel that sits upright behind the front grille of the car. Do not remove the radiator cap after your car has been running! This is hazardous because cooling systems are under immense heat and pressure.


The transmission lies on the rear side of your engine and beneath other parts; therefore, it’s not easily visible. The dipstick is located next to it for checking the transmission fluid level.


Brake Fluid Reservoir

The brake fluid reservoir sits beneath the hood in front of the steering wheel, and it’s usually transparent for quickly checking fluid levels without opening it. For a smooth braking system, it’s essential to have this filled with the proper amount of fluid.

Coolant Reservoir

Located near the radiator, coolant reservoirs contain the coolant fluid and are generally composed of translucent white plastic. Proper distribution of this fluid is integral to preventing damage to your car due to overheating.

Power Steering Fluid Reservoir

Power steering fluid reservoirs are frequently found on the passenger’s side of vehicles, though they can also be on the driver’s side. Attached to the cap, there will be a small dipstick. This fluid ensures the wheel turns smoothly, so if you’ve been feeling more resistance than usual while making turns in your vehicle, check its fluid levels or take it to a technician.

Windshield Washing Fluid Reservoir

Perhaps the simplest DIY task for car owners, it’s crucial to know where to top off your windshield wiping fluid. After opening the hood, look around the sides until you see a reservoir with a symbol of a windshield or liquid droplets on its cap (which is usually blue).

Kennedy Is Your Auto Part and Engine Expert

As a driver, a basic understanding of the parts within the engine compartment that keep your vehicle running like a well-oiled machine—literally—is invaluable. Whether you’re a resident needing auto service in Minnesota or just passing through, Kennedy Transmission offers a wide range of services to get you back on the road quickly and safely.

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