Only 1 in 25 People Can Answer These Common Car Questions. Can You?


By: Steven Symes

6 Min Quiz

Image: pexels

About This Quiz

Cars are complicated machines, especially those that are built today. Remember that your average car has thousands of components, plus complex electrical systems, electronics, sensors and more. All these systems work to help you get wherever you want to go, plus keep you safe, entertained and informed. It's a lot to keep track of. How much do you know about all that?

Really, most people are not that aware of how their car works, because they think it's too complicated. Fair enough, because cars are no longer the simple machines of yesteryear. But, if you're one of those rare individuals who likes to know what makes things tick, the upside is that you can repair all kinds of things on your modern vehicle, instead of paying someone else to do it. After all, if it's something you can take care of in less than 20 minutes, why would you pay someone a wad of cash to do it?

Still, there are common things about cars everyone should know, because they're necessary for properly caring for your vehicle. But, most people still don't know about them. Where do you land on the spectrum? Are you a car guru, just average, or do you need serious help? Take this quiz and find out.

Are spark plugs pre-gapped for your engine?

Spark plugs do come gapped already, but that doesn't mean they're in line with your engine's specs. Manufacturers make spark plugs that are the same configuration, but work on a whole range of engines, so it's impossible to have them all gapped to suit each engine, which is why you must check them yourself.


Why do some cars shoot flames out of their tailpipe?

Unless someone has installed a cheesy aftermarket flame kit for their exhaust, this is caused by the car running extra rich. The extra fuel that makes its way into the exhaust system burns up there, so flames shoot out the exhaust tip. Technically, you could do this with any vehicle.


What depth is generally considered unsafe for tire tread?

Some people like to use a penny to check for this depth, because when you can see all of Lincoln's head, it's time to get new tires. Of course, you could just use a tire tread depth gauge, which costs surprisingly little.


What is brake fade?

The most common cause of brake fade is when you ride the brakes, which generates so much heat the brake fluid boils and no longer applies the necessary pressure. Excessive friction alone, as well as mechanical problems, can also be the source of this dangerous issue.


How tight should you get the lug nuts on your car's wheels?

Every automaker will give you the lug nut torque specifications, which you really should follow when putting the wheels back on. If the lug nuts are too loose, you risk the wheels wobbling or coming off. If they're too tight, you can damage the wheel, bolts or the hub.


If the headlights on your car suddenly dim as you're driving on the freeway, what's likely the cause?

As you're driving, the power to run things like the radio, lights, etc. comes from the alternator, which also recharges the battery. The battery primarily provides enough spark to start the engine, which can be an issue if you have a bad alternator. Fortunately, it's relatively easy to have yours tested.


What does a car's 'cat' do?

Modern cars have catalytic converters as part of the exhaust system. The convert harmful gases in from the engine into less harmful or completely harmless gases, so less pollution goes into the air.


What kind of light beam do fog lights typically have?

Because fog lights are mounted low and scatter light broadly, they can help with seeing in bad visibility conditions, because they don't reflect light back into the driver's face. However, driving with them on in regular conditions can be annoying for other drivers, so keep that in mind.


How often should everyone change their oil?

Thanks to different engine designs, plus modern innovations in oil technology, some cars can go a long time between oil changes. The best thing to do is consult your owner's manual to ensure you're taking proper care of your vehicle, without spending too much on oil.


How do automakers test vehicle aerodynamics?

In modern times, automakers will use computer simulations to design exterior parts for a concept or prototype vehicle, which virtually measures aerodynamic drag. Still, they also put vehicles in a wind tunnel to get actual measurements, and make adjustments as they're necessary to ensure optimal efficiency and performance.


How does nitrous oxide help boost vehicle performance?

Back in World War II, the U.S. Air Force fogged nitrous oxide into the bombers' engines to help with quick air raids. The GIs brought this trick back home with them, and started doing the same thing with their cars. Because this chemical compound cools the air, you get more oxygen molecules in the cylinder, which leads to a more powerful burn, increasing power.


Which of the following isn't a method people use to clean foggy plastic headlight lenses?

Over time, the plastic headlight lenses cloud as they oxidize from sitting in UV light from the sun. All the methods people use to clear up this issue essentially strips a layer or more off the headlight lenses, removing the oxidization with it, so everything is clear again.


What usually causes milky oil?

Usually, milky oil comes from coolant mixing with it, which usually happens when the head gasket on your engine blows. It's possible for the two to mix otherwise, but not likely. Also, milky oil could be from moisture collecting in the combustion chambers.


Where do you place jack stands on your car?

The jack points for different vehicles vary, but usually they're behind the front wheels and in front of the rear wheels. Just look at the owner's manual to see where the manufacturer recommends placing them, and to see where you should jack up the car.


How much air should you put in your tires?

You should always look at the sticker placed in the driver's door jamb, the owner's manual, or call the dealership to see just how much air to put in your car's tires. It really does depend on the exact model, so never just guess or use any other information.


What is the primary reason for side curtain airbags?

While side curtain airbags certainly were made primarily to protect everyone's head, they also help keep your arms from flailing out the window, which could cause a serious injury, including your arm becoming trapped up the car if it rolls.


Where are most cabin air filters located?

You might think swapping out this air filter is difficult, but it's actually a cinch. Most modern cars have a simple way to unhook the glove box or flip it down far enough that you can reach the filter easily, making it a job anyone could do.


When jumping a car with a dead battery, which cable do you ground, and on which car?

Not grounding on the car that isn't working can have serious consequences, so just do it. Also, the working car should be tuned off as you make the connections, just so there isn't any risk of getting shocked or worse. And put the parking brake on both cars, just in case.


What's the risk of storing tires on the ground?

This risk is real if you're storing a car for the long term. If you have tires that are mounted to wheels or not, investing in a simple rack that gets them up off the ground is worth it. Once tires have flat spots, you likely need to buy replacements, and that gets expensive.


Which of the following activities won't necessarily void your car's manufacturer warranty?

Some dealerships will try to convince you that your car must be serviced there for the warranty to not be voided. If you have a reputable shop do the manufacturer-recommended maintenance, you shouldn't have a problem.


What does a car's differential do?

Without a differential, your car would have a problem with turns. It allows the inside wheel to spin less than the outside as you go through a turn. Rear-wheel-drive cars usually have the differential in a separate housing, where it uses its own lubrication system.


What powers your car's heater?

As the coolant flows out of your car's engine, it goes to a compartment called the heater core. There, heat from the coolant can be blown by a fan into the cabin. That means the coolant is what really powers your car's heater, which is why being low on coolant can suddenly turn the heater cold.


What does a turbocharger recycle on a car?

Turbochargers literally run off the exhaust gases from your car, essentially recycling them. This gives your engine an instant boost as more air is crammed into the cylinders, especially considering most modern turbos use an intercooler to avoid pushing hot exhaust gases back into the combustion chambers.


How big does damage on a tire need to be for it to be not repairable?

Not only does a puncture need to be small for it to be repairable, it can't be on the shoulder or sidewall, otherwise you'll have to just replace the tire.


The term "direct injection" refers to what?

Direct injection means the fuel injectors spray right into the combustion chamber. Some engines are set up for this to happen right before the spark plugs ignite the air-fuel mixture, which can make everything run more efficiently.


What does overdrive on an automatic transmission do?

So many people talk about kicking things into overdrive, which means working harder and pushing everything to the limit. In cars, overdrive actually helps the transmission work less by using a higher gear, which in turn saves on gas.


How does fuel in a diesel engine combust?

Unlike gasoline engines, diesel engines don't have spark plugs to ignite the fuel. Instead, they place the air-fuel mixture under so much pressure, the fuel combusts, which is partly what makes them so efficient.


What is the difference between a non-interference and interference engine?

If you have an interference engine, when the timing belt or chain breaks, you might be facing some serious internal damage, requiring a rebuild. Of course, non-interference engines don't present this challenge.


On modern cars, a loose gas cap can result in what?

Depending on your car, you need to turn the gas cap until it clicks once or three times. It's also a good idea to give a little tug on the cap, ensuring it's seated all the way, before you turn on the engine and start driving.


A tire that's under-inflated will result in what?

There are a lot of drawbacks to not inflating your car's tires enough, including bad fuel efficiency, decreased acceleration, and poor cornering performance. You should check the inflation regularly, like once every month or so, to prevent these problems.


Which of the following isn't something polishing a car does versus just waxing it?

Really, you should be waxing and polishing your car's paint regularly, not just one or the other. Both are key to having a car that looks excellent for some time, instead of dealing with paint that has a poor appearance.


What will a slipped ignition wire boot result in?

When the boot on an ignition wire, which is supposed to sit firmly on the lip around a spark plug well, slips off, your engine loses some compression. That means it runs rougher than before, which hurts performance as well as makes for a less comfortable ride. Fortunately, this problem is super easy to correct.


In cold weather, a small windshield crack can do what?

All it takes is a little bit of moisture getting into the crack, and as it freezes that water expands quickly. The result is a small crack becoming a big one in about one second, sometimes so violently it will scare you as the driver.


What does the accelerator pedal in a modern car control?

Whether electronically or mechanically, the accelerator pedal in your car determines how wide the throttle opens. The onboard computer then adjusts the flow of fuel accordingly.


What is the most common cause of a car horn suddenly not working?

Something as little and simple as a fuse can cause all kinds of electrical problems on your car. The horn is electrical, so you should always check the fuse first before deciding the horn itself needs servicing.


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