Can You Ace This Car Parts Quiz?


By: Steven Symes

6 Min Quiz

Image: shutterstock

About This Quiz

According to Toyota, the average modern car contains about 30,000 parts. That's pretty staggering, but if you consider that the grille alone is often held in place by multiple screws, bolts, clips or whatever else, and that's one of the least complex setups on most vehicles. Engines have become increasingly complex, thanks to the push to boost efficiency and lower emissions, as well as ensure reliable operation in all kinds of conditions.

Years ago, cars were fairly simple beasts. They could be worked on by shade tree mechanics, and just about every car owner changed their own oil and did other regular maintenance. Today's computer-festooned vehicles have made that a risky proposition.

There's a reason why automakers have large teams of engineers and designers working hard to develop a new vehicle. They often borrow components and even entire setups from existing models, because creating the whole thing from scratch requires considerable time and money. The good news is that mechanics can learn how most systems on a particular brand are set up more easily, and even find similarities among various competing brands.

To most people, all of this is a huge mystery. Are you an expert mechanic who can fix just about anything? Flex your car parts knowledge now by taking this quiz!

When replacing a gasket, which of the following must you do with the old one?

Depending on the gasket, it might leave a residue behind, or the entire gasket might be stuck to the car part. Special gasket removal tools will make the cleanup quick, without damaging any other surfaces.


When the engine is turned off and at rest, where does most of the oil collect?

The portion of the engine where oil runs and collects is called the sump. When you first start up the engine, the pump starts to channel the oil out of the sump and to the different areas of the engine, but it can take a few minutes to reach that point.


What is the ultimate purpose of a sway bar?

A sway bar is designed as extra bracing, forcing the tires to stay down and in contact with the ground, instead of lifting off as the car goes through turns. Essentially, this improves handling and safety.


The EGR valve is part of which system?

An exhaust gas recirculation valve has a design that reduces nitrogen oxide emissions from internal combustion engines. If it's malfunctioning, your vehicle might not pass local emissions tests.


If your wiper blades are new and not worn out, yet they still leave streaks on the glass, which of the following could possibly be an explanation?

Most people don't think to clean their wiper blades, but they should. A soft cloth will remove dirt and other debris, which can contribute to streaks being left behind on the glass. Another potential cause is that the springs on the wiper arms are worn out.


If you don't have air tools on hand and must use a tire iron or torque wrench, when should you first loosen or completely tighten lug nuts?

Assuming you're not using a lift, because if you were you'd probably have air tools as well, trying to loosen or completely tighten lug nuts with the car supported by a jack or even jack stands isn't as effective and can pose a danger.


What keeps a differential's parts from grinding against each other?

You should never just ignore the differential on your vehicle, or you might find that you need to buy another differential. Refer to the owner's manual for the right oil weight and GL rating, or you could still experience problems.


Which component supplies power for all the on-board electrical functions of a car while it's running?

A car's alternator is belt-driven, so it depends on the engine to make it work. The battery is used to get the engine going, and then is recharged by the alternator, which powers everything from the headlights to your sound system.


On mechanical, not electronic setups, what component transfers pedal movement to the brake or throttle systems in a car?

Many newer cars feature electronic pedals, which send an electrical impulse as you push or let up on them, but older setups involved the pedal movement actuating a pushrod, which in turn would apply brake pressure or open the throttle body wider.


What is the part that keeps the piston and connecting rod attached to each other?

The wrist pin is a component often forgotten about by those who don't do engine rebuilds, but it's a point of failure in certain situations. This component has to deal with tremendous forces, so it must be equally strong to endure them and not break.


Which component helps exhaust gases to be less harmful to the environment?

Catalytic converters contain precious metals, which literally convert highly harmful gases into gases that either aren't harmful, or aren't nearly as harmful. They essentially catalyze a redox reaction to make this possible.


What on camshafts determines when and how much valves move?

Camshafts aren't perfectly round, but instead feature oblong lobes, which don't all line up with each other. These control how the intake and exhaust valves move, including when, for how long, and how much.


What does the shifter fork do?

People who don't really know how cars work probably think that as you move the stick shift, it's directly moving gears around in the transmission. It's the selector fork that fills this important role, and is what you hear grinding if you mess up.


Which of the following parts actually helps reduce vibrations you feel from the engine?

While engine mounts certainly fill the important role of holding the engine in place, they also act as a damper or absorber of vibrations. Some engine mounts have fairly complex setups for that reason, which can make them expensive to replace.


If you only have to plug in new headlights or other electrical components, instead of having to create connections otherwise, that's thanks to what kind of a part?

If you have the right kind of wiring harness, all the necessary wires, terminals and simple connectors are already set up for you to use. Without this, you'd have to figure out the wiring setup from scratch.


What part is responsible for providing heat for your car's interior?

As coolant leaves the engine, it's extremely hot. Some of it will flow into the heater core, a device that looks similar to a small radiator, which is located usually behind the dashboard. Of course, if the coolant level is too low, the heater core doesn't work.


This part puts constant force on the drive plate, helping to transfer energy from the engine to the transmission.

Pressure plates are able to keep contact with the driven plate through the diaphragm spring, or on earlier models it's a group of coil springs.


What triggers the horn in modern cars?

The average car in the United States has two horns, each producing a different pitch so everyone hears a clear chord. The electrical pulse triggers a spring steel diaphragm, through a switch and coiled wire, making the sound.


When combustion happens in the cylinders, which engine part is pushed down first?

Since the piston sits right under the explosion of gas and oxygen, it's the first part to feel the pressure. That's transferred to the connecting rod and then the crankshaft, converting the movement into a twisting motion.


What is a type of electrical generator used in some vehicles, but it doesn't produce a continuous electrical current?

Old cars and some race vehicles use magnetos instead of a regular alternator. It's also common on lawn mowers, chain saws and other small engines. It generates a lot of high voltage at just the right time, instead of always producing about the same voltage.


With most washer jets, how do you clear debris and change the direction they spray?

Because spray nozzles have small openings, you need something that can fit inside of it without damaging anything. From there, you can knock out dirt, salt, or whatever else is stuck, plus point the nozzle in a different direction, if it's not hitting the intended target squarely.


This is the vehicle component that will ignite the air-fuel mixture in the cylinders.

Spark plugs shoot an electrical pulse across the gap at the tip, which creates a spark in the air. That small spark will trigger the combustion process, once the air and fuel have been compressed in the cylinder, unlocking the energy.


Where is the O2 sensor located in a car?

The whole purpose of the O2 sensor is to measure how much unburned oxygen is present in the exhaust gases. The car's ECU uses this feedback to change the air-fuel mixture for the most efficient operation possible.


If you engage the parking brake on a hill and the car starts to roll down, what might need to be adjusted or replaced?

The parking brake cable can stretch out over time and even break, making it necessary to adjust or replace. Another possibility is that the brake pads for the emergency brake have worn out, although that's usually less likely.


Control arms perform what job for a car?

While the name might make them sound like they control something, control arms actually just bring stability to the suspension system, and in turn allow the car to maneuver with greater precision.


What does a breather connect to in a car?

The breather is part of the ventilation system for a crankcase, which allows gases from that area of the engine to escape in a measured or controlled way. Without this, your engine could experience any number of problems.


What does an exhaust resonator do?

Because sound moves in waves, engineers can create resonators that will get rid of any undesirable qualities, whatever those may be. The design of each resonator is different, and removing it will greatly change how your vehicle sounds.


If different lights on a car dim while the engine is running, what is most likely the part that needs replacing?

The source of power for on-board electrical systems while any car is running, the alternator is an essential component. While a bad electrical connection might make one set of lights like the gauge cluster or one headlight dim, multiple lights dimming likely means the alternator is going out.


What is a heavy disc attached to the end of the engine's crankshaft?

The flywheel is a key component to transferring the rotational motion of the crankshaft to the transmission, as it helps maintain smooth and even motion.


What components transfer electricity to the spark plugs?

The ignition wires are the second-to-last part of the car's ignition system, providing the final connection to the spark plugs. They also have a rubber boots that seal around the spark plug wells to maintain proper compression.


What assembly do you attach the wheels of a car to?

The wheel hub assembly sits between the brakes, whether they are of the disc or drum variety, and the actual drive axle. The bolts you use to mount the wheel are part of the hub.


What is the part of the brake system that actually pushes the pads against the rotors?

The calipers pinch toward each other as hydraulic pressure increases, pressing the brake pads against the rotors, slowing or stopping the vehicle. The amount of force exerted by calipers is based much on the number of pistons present in them.


What is the job of an airbag inflator?

Airbags essentially explode out of their hiding spots in a crash, thanks to the inflators, which pump them up in essentially no time. Exactly how the inflator does that depends on the design.


What component spins in the cylinder head of DOHC and SOHC engines?

The camshaft isn't perfectly round, so it's not quite like a rod. Instead, the different lobes are shaped to control how the exhaust and intake valves open, including how long they stay open and closed, impacting performance accordingly.


What is the part that attaches to the steering wheel?

Especially if a car has a rack-and-pinion steering setup, but even if it doesn't, the steering wheel sits on and rotates at the end of the steering column. The steering column then attaches to the intermediate shaft.


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