Do You Know What's Good for Your Car and What's Not?

By: Bambi Turner
Image: alle12/E+/Getty Images

About This Quiz

Think you know the secrets for getting the best gas mileage for your car, or how to protect yourself and your ride if you end up in a skid? Know when and how to change your oil, top off your fluids or swap out old filters? Take our quiz to see how much you really know about what your care actually needs, and what it doesn't.

Kelley Blue Book reported the cost of a new car at just over $36,000 at the start of 2018. That's a big chunk of change for anyone without a trust fund, and it doesn't even include the thousands of extra dollars spent annually to fuel, insure and maintain your ride. Despite transportation ranking as the second biggest expense behind rent for many people, few know what it takes to actually get the most from a car, including how to cut gas costs, stay safe while driving, and keep the car on the road for many years to come.

Sure, you can splurge on regular trips to the dealership to have your car maintained, but that won't solve all your problems. There's plenty of opportunity to boost your car's performance, or totally destroy it, during everyday driving and maintenance. But do you know what's good for your car and what isn't? Take our quiz to find out!

When should you splurge at the pump and fill your car with premium gas?

Premium gas can easily cost 20 to 40 cents more than good old unleaded, but many drivers shell out the extra cash at the pump, believing premium is better for the car. Don't waste your money!

Do you really have to replace all four tires when one ends up shredded?

Forget the old advice about shelling out big bucks to replace all of your tires at once. You only need to replace them all at the same time if your car has AWD, according to Consumer Reports. If you have front or rear-wheel drive, play it safe by replacing tires in pairs, but don't worry about swapping out all four at once.

How often do you really have to change your oil?

That whole rule about changing oil every 3,000 miles no longer holds true with most cars. You can typically wait between 5,000 and 7,500 miles, according to AAA. Of course, to do right by your car, check your manual to see what the manufacturer recommends.

Assuming your car is less than 20 years old, how long should you let it warm up in the morning before you hit the road?

Old cars had carburetors that needed a few minutes to warm up so they could pull in the right ratio of fuel and air. Cars manufactured since the early '90s are equipped with the wonder of electronic fuel injection, which means your car only needs a few seconds to warm up.

When is it a good idea to fill the engine in your car with jet fuel?

One car myth that refuses to die swears that putting jet fuel in your engine will help you max out performance and speed. Sadly, the opposite is true, and filling your tank with jet fuel will do nothing more than stall your car and ruin your day.

What should you do when you're pumping gas and the pump automatically shuts off?

There's a really good reason that the pump automatically shuts off when your gas tank is full; it's because continuing to add gas beyond this point is seriously bad news. Topping off the tank not only wastes money, but also forces liquid gas into your vapor collector, which can lead to engine problems.

What should you do if you lose control of the car in a ride equipped with anti-lock brakes?

Old-school advice about pumping the brakes doesn't apply to modern rides with anti-lock brakes. All of that pumping just causes a car with ABS to take longer to stop. Instead, keep your foot firmly pressed on the brake, and be prepared for the pedal to pulse. That pulsing is the ABS doing its job.

What is the most common disadvantage to a filthy engine air filter?

According to AAA, a dirty air filter has no negative impact on gas mileage if you're driving a car with modern fuel injection. While a dirty air filter can cut the power of your engine, most only need to be replaced every 20,000 miles or so (though you should always check your manual to make sure).

Which gets better gas mileage on average, a dirty car or one that's freshly washed?

Believe it or not, "MythBusters" actually took on the clean vs. dirty debate in episode 137 of the show. They found that at highway speeds, dirt on the car cuts fuel economy by around 10 percent. That means you can reduce the pain at the pump with a bucket of sudsy water and some elbow grease.

How long can you let your car idle before you will lose less gas by switching it off, then back on again when you are ready to roll?

Want to improve fuel economy and reduce your impact on the earth? Turn off your engine any time you have to idle your car for 10 seconds or more. After 10 seconds of idling, it's more efficient and cost-effective to turn off the car and switch it back on when you're ready to drive again.

What is the very best solution for your car if you accidentally fill your gas tank with diesel?

In the U.S., most diesel nozzles aren't designed to fit into a gas tank, but some drivers manage to find a way to accidentally fuel up their gas-powered car with diesel. If this happens, the best way to save your car from disaster is to keep your car turned off and have the tank drained.

How much are you likely to cut your gas costs if you fill up early in the morning when temperatures are low rather than later in the day?

Those rumors about filling up your tank early in the morning to save money aren't rooted in reality, according to Consumer Reports. Thanks to double-walled underground storage tanks at the gas station, fuel stays the same temperature regardless of what the thermometer in your car is saying.

What should you do with your truck's tailgate if your goal is to maximize fuel economy?

No, opening your tailgate before you hit the road won't save on gas. According to MythBusters, keeping the tailgate closed creates a separate airflow area in the truck's bed. In a test of two identical, trucks, the show's hosts found that a truck with the tailgate up traveled 30 miles further.

Which cars benefit the most from regular tuneups?

Cars built before the year 2000 require regular tuneups to adjust things like the carburetor, condenser and spark plugs. Modern cars use new technology, including spark plugs that can last 100,000 miles or more, and don't benefit from routine tuneups, according to Consumer Reports.

How much do you reduce your fuel economy when you turn on the AC in the summer?

Fueleconomy.gov estimates that switching on the AC cuts fuel economy by around 25 percent. An experiment by the MythBusters team found that driving with the windows down wastes much less fuel than switching on the AC when traveling at 45 mph.

Which of these is NOT a benefit associated with using manual transmission?

If you can manage a stick shift, this technology offers a lot of advantages over an automatic, from improved acceleration to better fuel economy to a cheaper sticker price on average. You'll find less variety, and may have some resale difficulties.

Which of these aftermarket products is proven to reduce emissions and improve fuel economy?

Both the EPA and the Federal Trade Commission warn that after-market gas-saving or emissions-reducing products don't work, and many actually reduce fuel economy or increase pollution from your ride. The EPA states that of all the devices it has tested, none have worked.

What's the best way to save yourself and your car if you find yourself skidding?

The old adage to steer into a skid has been replaced with new advice. To free yourself from the skid, keep your eyes pointed in the direction you want to travel while also removing your foot from the gas. This should help you regain control and keep both you and your car safe.

What's most likely to happen to your car if you use off-brand gasoline?

All gas starts off the same at the refinery before required EPA additives are mixed in. Many brands then add there own additives, but there are mixed reports about whether these proprietary additives actually help your car.

Which of these is true about driving around with under-inflated tires?

It's hard to believe that a little air can make such a difference, but under-inflating your tires not only shortens their lives and makes you less safe on the road, but can also cut fuel economy. In fact, Fueleconomy.gov estimates that you can improve mileage by 0.6% simply by properly inflatng your tires.

What should you do if you go to the station to fill up with gas and you see a tanker truck refilling the station's tanks?

One car myth warns drivers that tankers stir up dirt and sludge when they fill the underground tanks at gas stations. While this is true, Snopes.com reassures drivers that it shouldn't stop you from filling up. Between the fuel filters in your car and the filters required at gas stations in the U.S., this extra debris can't harm your car.

What car part could potentially be damaged if you overload your key chain?

Believe it or not, putting your car key on an overloaded key chain can put so much stress on your ignition that it could eventually keep your car from starting properly. In 2014, GM recalled nearly 800,000 cars because of an ignition issue that could be set off by factors which included a heavy key chain.

Which of these should you do if you plan to store your car for a month or more?

To keep your care in top shape when it's in storage, you must take some steps to prepare it first. This includes filling it with gas, topping off the fluids, cleaning any gunk off of the undercarriage and filling the tires.

When is it a good idea to block your tailpipe with a rag?

A blocked tailpipe is a major damage to your health and to your car, but it often makes sense to stuff the tailpipe shut with a rag or steel wool when you're storing your vehicle. This prevents critters from getting into the car and building a home. Of course, it's critical to remove the blockage before you start the car again.

When is it OK to add water to your windshield washer reservoir?

Windshield wiper fluid is made of solvents and antifreeze. Adding water in place of this special fluid will not only put you at risk for frozen tubes, hoses and tanks, but is also associated with a risk of Legionnaire's disease. Stay safe and stick to washer fluid.

What benefit do tire valve caps provide for your car?

Those valve caps on your tires might not look like much, and many are tempted to forget about them if one gets lost or broken. Keeping these caps in place not only reduces air leaks and keeps your ride looking polished and together, but also keeps out grime and dirt.

Which of these common household objects is a great tool for testing tire tread depth?

The DOT requires you to replace tires with a tread depth of less than 2/32 of an inch. If you can stick a penny between the treads with the top of Lincoln's head facing down, and his head disappears behind the treads, your tires are still safe to use. If the top of his head is visible, it's time for new tires.

When is it recommended to substitute transmission fluid for brake fluid?

They may all go by the name fluid, but the liquids used in your brakes are very different from those used in your engine, transmission or power steering. Almost all car fluids are oil-based, while brake fluid is alcohol-based to help control excess moisture in brake lines.

When you see numbers like 10W-30 on a bottle of motor oil, what are those numbers referring to?

The numbers you see on oil refers to the viscosity, or thickness. Every car is designed to work best with a specific oil viscosity, so always check the cap on your oil tank, or your car manual, to choose the right oil for your ride.

Winter weather is hard on cars. Which of these is not a good way to maximize fuel economy when it's cold outside?

Fuel economy is 12 to 22 percent lower in the winter than in the summer. To save stress on your car and keep fuel costs low, try to combine trips, park in a garage to keep your car warm and keep extras like seat warmers turned off. Idling is a major waste of gas.

What must you add to full-strength antifreeze before adding it to your car?

Antifreeze is a critical fluid for maintaining a healthy engine, but shouldn't be used alone. It must be mixed with water in a 50/50 ratio before adding it to the car. Some antifreeze products are already diluted, so always check the label to be sure.

How long should you baby your new car when breaking it in to maximize lifetime performance?

The first 500 to 1,000 miles of driving in a new car is considered the break-in period. Avoid revving your engine, towing, extreme speeds and hard stops during this period to maximize the life of your engine and related systems.

What happens if you mix two different colors of coolant together in your car?

There are two kinds of coolant, including orange Dexcool and the older green ethylene glycol. Mixing these varieties in your engine creates a gel that hardens in the engine, grinding your car to a halt.

Why must you run your air conditioner periodically in the winter?

No matter how cold it is where you live, it's good for your air conditioning system if you turn it on every few weeks throughout the winter. This ensures the system stays lubricated, keeps seals from drying out and reduces mold and moisture in the lines.

How often should you rotate your tires to stay safe on the road and extend the life of your wheels?

Tire rotation ensures even wear and reliable traction, keeping you safer on the road. Bridgestone recommends rotating tires every 5,000 miles, though it's always a good idea to check your manual to see what the manufacturer suggests.

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