How Much Do You Know About Engine Myths?


By: Ian Fortey

7 Min Quiz

Image: urbazon / E+ / Getty Images

About This Quiz

The automotive world is absolutely chock full of misinformation, half-truths, full-on lies and myths as far as the eye can see. It's no big surprise though; there will always be people who base opinions on anecdotal evidence or things that aren't entirely reliable. These rumors and half-truths get spread around and become the myths that everyone ends up believing. And then, of course, there is the momentum of technology. What was true of a car in the '60s or the '80s is often not true today. Technology advances so much that we need to adapt our understanding of how engines work because they really are different today than they once were. After all, is a computer from 20 years ago as powerful as one today? Not at all.

So if you've ever been told that you need to change your oil every 3,000 miles, did you ask why? And is it possible you really don't need to winterize a car, or let it warm up for a few minutes before you go for a drive on a cold, January morning? Does a dirty car drive faster than one that's freshly cleaned? If you think you know your engine myths, then why not take the quiz and show us your stuff?

Why do you need to warm up your engine in the winter?

This is a pretty pervasive myth, and it's just not true. You don't need to warm up a car in the winter before driving, and, in fact, driving it to warm it up is the best way to get it to run smoothly. That allows even distribution of oil, prevents unnecessary wear and tear, and saves fuel economy.


Is it better to drive with the A/C on or with the windows open?

This is one of the worst myths to debunk because people keep giving you different answers. The "Mythbusters" tested this and found that an SUV with open windows goes further than one using A/C. But if you're on the highway, you're going to want to use the A/C, especially at high speeds because windows can add some severe wind resistance.


What's more fuel efficient, a clean car or a dirty one?

There's a popular belief that a dirty car is actually more fuel-efficient because the dirt on a car acts like the dimples on a golf ball, allowing it to be more aerodynamic. The opposite is actually true, and a dirtier car will increase drag.


When do you need to change your oil?

The old rule of thumb has long been to change the oil every 3,000 miles, but that's not really true of most cars anymore, and neither is 5,000 or 10,000. The smart thing to do is check your owner's manual because it's going to have the best answer that's relevant to your specific vehicle instead of a generalization. That said, modern engines and oil are so efficient that 3,000 miles is almost always too soon.


Is it true there's no replacement for displacement?

The statement "there's no replacement for displacement" basically means a big engine will always be more powerful simply because it's bigger. And for a long time, that was true, but technology has caught up to big engines and forced induction has made it possible for smaller engines to have higher energy outputs.


On average, how often do you need to take a new model car to the shop to get the engine tuned up?

Never trust a mechanic who says you need an engine tune-up on a modern car because you don't. Engine tune-ups are like antenna adjustments for a TV; they don't make sense with new technology and aren't necessary. Now, if you have an older model, that's another story, but if your car is less than 20 years old, forget it.


Is a V6 engine faster than a V8 engine?

V8 engines are bigger and generally more powerful, but a lighter car with a turbocharged V6 engine may very well be faster than a car with a V8. There are more factors to consider than just engine size.


If your dipstick shows that your oil is dirty, does it need to be changed right away?

When you first pour out that oil, it may very well look like golden honey, and then next time you check, it's dark and filthy. Don't change it, though, unless it's time. The point of the oil is to get dirty; it's there to clean and lubricate the engine. It would be weirder if your oil weren't dirty after some use.


Is it true that the motors in a hybrid car are slower than combustion engines?

Early generation hybrid cars were not performance beasts by any standard, but they've come a long way. They used to be slower than most comparable vehicles with combustion engines, but not only is that no longer the case, some hybrid engines are more powerful than similar combustion ones.


Will premium fuel make your engine run better?

Higher octane fuel is only useful if your engine was made for it. Performance cars need performance fuel, but the average car on the street has no need for higher octane fuel, and it will literally just be a waste of money to buy premium gas for an engine not designed for it.


What does the "W" in 5W30 motor oil stand for?

People often think the "W" in motor oil names means weight since they're referring to something like "30 weight" oil. It does not stand for weight, however, rather winter. The first number, in this case, the 5, is a reference to the viscosity of this oil during the winter. The 30 is the viscosity at normal temperatures.


Are fuel economy figures based on real world driving conditions?

Fuel economy numbers are notoriously shady, and sometimes manufacturers even have to revise them and compensate customers for misleading them. EPA figures are often devised through some very crafty means to milk every last inch from a drive to make a car's fuel economy seem far better than it really is.


Is it true some jet fuel will make your car into a performance monster?

Despite the fact a jet can fly at speeds over 500 miles per hour, that doesn't have a lot to do with the fuel in them, and jet fuel is 100% bad news for your car. Jet fuel is basically kerosene, and a regular vehicle cannot burn it.


Will fueling up in the morning make your car perform better?

There's a popular myth that fueling up in the morning is better for your car as in the morning, the fuel is denser, and so you're going to get more for your money. The fact that fuel is stored in underground tanks in which the temperature barely changes means this isn't true, and there's no ideal time to gas up.


Why do people say you should avoid first-year car models?

It's a widespread belief that the first year a car comes out is one to avoid because it's going to be super buggy. It could be transmission issues, fuel line problems, or a whole host of other concerns. The fact is, you can't really know, though. Some first-year cars definitely don't perform as well as later models, but some first years are amazing.


Which of these is untrue of an electric car?

There are a lot of myths about electric cars, including that they're too slow compared to standard cars, or they have a limited range, which Tesla would certainly disagree with. Also, people believe they're more expensive, which is quite inaccurate as the cost of fueling an electric car is a fraction of gas.


If your car's engine has an engine control module only a professional should service it, right?

The engine control module, or ECM, is the computer that monitors most of your car's functioning to keep it optimized. Though it's a precision piece of equipment, so is every part of your vehicle, and if you have the know-how to service parts of it yourself, then do so. If not, take it to a pro.


Is off-brand gas a danger to your engine like some people think?

For the most part, off-brand gas, the gas you buy at a corner store rather than a big chain like Shell or Mobil, is going to be fine for your car. It'll have few additives, but if you don't have a high-performance engine, that's unlikely to make a big difference.


Is it more or less efficient to make only right turns in your car?

Have you ever seen a UPS truck turn left? Probably not, and the reason is that they're not supposed to unless it's 100% necessary. The amount of time you waste in your car waiting to turn left burns far more fuel than the extra distance you'll travel by only making right turns to get where you're going. Weird but true.


Does a bigger tail pipe improve engine performance?

A free-flow exhaust system may improve the overall performance of your car's engine and fuel economy, but that's an entire exhaust system. A simple tailpipe upgrade to a larger size will not improve the car's overall performance.


Does sugar in a gas tank destroy a car's engine?

This is a classic prank everyone has heard of, putting sugar in a gas tank to kill an engine. The thing is, it doesn't work. Sugar doesn' dissolve in gasoline, and your filter would catch any that moves down the line. What it will do is take up a ton of space in your tank, ruining your fuel efficiency, and you'll have to get a mechanic to remove and clean the tank.


Do you need to winterize a car?

Older cars were not as able to handle the cold weather as newer cars, and so winterizing them, replacing the fluids with ones meant to handle sub-zero temperatures, was a good idea. Nowadays, however, you don't need to winterize a car at all.


Police have to chase down speeders so they have special edition engines that civilian cars don't have, right?

There's a popular belief that cop cars are souped-up much better than your average car with a powerful engine made for pursuing criminals. While police do have performance engines, they're not police-exclusive in any way.


Rumors have existed for ages about engines that run on water. Do such things exist?

There is no practical, real-world engine that runs on water, though there have been many fraudulent claims of them. Since water can't burn, an engine would need to separate that water into hydrogen and oxygen, but the power necessary to do that would be more than the engine itself can produce.


What does overdrive do in a car?

Overdrive isn't really a thing in modern cars, but contrary to what some people used to believe, it's not a tool for making your car go faster, either, at least not in the "nitrous boost" sense. Overdrive simply puts a vehicle in a higher gear to allow for better fuel economy and maintenance of high speed.


What's going to give your truck the worst gas mileage?

There's a long-standing myth that driving with your tailgate down will increase gas mileage, the idea being that with it up, you're trapping air and creating drag. In fact, tailgate up is much more efficient because it creates a bubble of air that makes the truck more aerodynamic, Lowering the tailgate breaks this bubble and increases drag.


What's the danger of using synthetic oil?

Some people believe that using synthetic oil will cause tubes and gaskets to break down and lead to leaks. In fact, synthetic oil is thinner than normal oil and may expose a pre-existing leak, but it will not cause one.


Is it true that a cold air intake can improve your engine's performance?

A properly installed cold air intake can offer a bit of a performance boost with some manufacturers claiming that you can get 5 to 20 horsepower extra out of such a device. As long as it's not exposed enough to suck up water and stall out the engine, it should be OK.


What's the danger of switching from synthetic oil to regular oil and back?

Some people believe that switching up your motor oil from synthetic to normal and back will cause serious damage to your car, but that's just not the case. When you think about it, that's what a synthetic blend is — it's both kinds together.


Is it a good idea to buy a performance chip for your engine?

You can find performance chips for sale on eBay and other sites that claim to increase computer performance to push your car's limits and improve performance. In fact, a lot of them are so useless, all they do is turn on a light to dupe you into thinking something is happening.


Will switching brands of oil damage your engine?

For the most part, motor oil is motor oil, and you don't need to worry about switching brands. The difference between one and another is negligible and should have little to no effect at all on the way your engine functions.


How often should you add some additives to your oil?

Performance-enhancing fuel additives are great, but they're also unnecessary since your oil probably has everything it needs included in it already. Adding more will just be a waste of money and potentially cause worse performance overall.


How often should you change your transmission fluid?

Some mechanics will tell you that transmission fluid should be changed every 50,000 miles, but that's like saying oil needs to be changed every 3,000 miles. It's not true, and some vehicles can go over 150,000 miles without having the transmission fluid flushed.


Which is faster, manual or automatic?

Some people will tell you that a manual transmission is always going to give you more control and be a faster automobile, but that's not 100% true. In fact, many newer cars with automatic transmission perform much better than manual.


You should change all your fluids at the same time, right?

It's mostly just a lazy option to try to change all your fluids at the same time for the sake of convenience. Coolant, oil and transmission fluid all have different lifespans and times they'll need to be changed.


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