15 Things You Do to Your Car That Mechanics Wouldn’t

Yes, you need to "warm up" your car.

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Portrait of a mechanic at work in his garage
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Maintain Your Car From a Mechanic’s Perspective

You may not think twice about many of your habits surrounding use and care of your vehicle. Seen from the perspective of a mechanic, some of these ‘harmless’ behaviors inflict wear and tear on your car that you might not expect. And they’re totally separate from the things you shouldn’t do in your car. So, try to avoid these destructive habits.

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Young black businessman driver wearing expensive watch sitting inside the car driving holding steering wheel close-up back view
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Stopping and Starting Aggressively

As glamorous as movies and TV shows make it seem to slam on the accelerator and peel out onto the road, this is really not good for your car. Neither is braking super abruptly. Though you can sometimes justify the latter for safety reasons, you should definitely avoid doing it willy-nilly.

“Love to peel away from a stop? Your mechanic will love you for it,” warns Matt Schmitz, assistant managing editor of Cars.com. “Driving gently will prolong your car’s life, and it will improve fuel efficiency and overall safety in the process.”

In addition, slamming on the brakes repeatedly can wear on (what else?) the brakes.

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Price display on three different levels of gasoline in US dollars. Price gouging?
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Using Fuel With the Wrong Octane Rating

You probably already know that putting diesel in a gas car can be dangerous—and if not, this is what can happen if you put diesel fuel in a gas-burning car. But this applies to different octane ratings of gasoline, too. “Vehicles are designed to run on a specific grade [of] gas,” says Jill Trotta, VP of the Auto Team at RepairPal.

For instance, using lower-grade fuel in a high-performance vehicle can cause a decline in performance. And while doing the opposite, putting higher-grade fuel into a car than can run on regular ol’ gas, won’t cause any harm, there’s just no reason to do it. “[It’s] a waste of money and any performance benefit noted is most likely perceived and not real,” Trotta explains.

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Manual car wash in car wash shop service with employee worker in back.
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Neglecting Cleaning

How often do you clean your car? Probably not often enough, according to Richard Reina, product training director at CARiD.com. In addition to keeping the interior clean to prevent germs from accumulating on the surfaces you touch, keep an eye on the exterior as well.

The paint and metal surfaces can deteriorate if you’re constantly letting dirt build up. And keep in mind that even the most thorough washing of the exterior of your car will probably neglect the undercarriage. “[The undercarriage] should receive a good wash at least once a quarter to remove any chemicals or debris that can cause corrosion and ultimately result in rust holes,” Reina says.

He adds that cleaning your car is especially important during weather changes. And, of course, keeping the body clean and in good shape also makes your car more sellable.

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Engine start button

Driving Full-Throttle Right Away

The directive that you need to “warm up” your car by letting your engine idle for a few minutes before you drive is somewhat outdated—it only applies to old carbureted engines. Idling your combustion engine like that really just wastes fuel; the best way to “warm up” your engine is by, well, driving it.

You still should give your engine some time to warm up, but instead of letting your engine idle, you should just take care to “go easy on” your car as you begin to drive. “An engine will warm up faster if you drive lightly—no hard acceleration—for the first couple of minutes,” says Jenni Newman, editor-in-chief at Cars.com.

You should especially take care to do this if you’re heading right onto a highway or climbing a hill.

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Close up of hand of female driver shifting gear stick before driving car
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Shifting Gears Aggressively

We’ve already been over how hitting the gas and brakes aggressively and forcing your car to respond puts unnecessary strain on it. But the same is true for shifting gears abruptly and then immediately trying to get the car to go again. (Or stopping the car—abruptly throwing your car into park can be just as damaging as shifting rapidly between Drive and Reverse.)

This is another tactic that seems beneficial when you’re in a rush, but Schmitz cautions against it. “Shifting while your car is still in motion can damage your transmission,” he says. Make sure your car is at a complete stop before shifting gears.

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empty fuel tank

Running the Gas Tank Down Near Empty

This is another finger-wagging driving tip that you may have heard but probably don’t give much thought to following. And, of course, sometimes driving until you’re very low on gas can’t be avoided. But you should probably be trying! Try these great tips to get better gas mileage.

“Driving while the tank is low is a bad habit that mechanics and engineers will always avoid,” says Jake McKenzie, Content Manager at Auto Accessories Garage. “The detritus and debris that are in your gas tank will typically settle on the bottom,” McKenzie explains. “When you let your vehicle run on fumes, you’ll be pumping a concentrated amount of gunk through your engine.” And, needless to say, that’s not great for it.

In addition, having plenty of gas in your tank will actually make your vehicle run more efficiently. “You’ll actually get better gas mileage when you have more gas in the tank,” McKenzie says. “Even though you’ll be carrying more weight, when there is less empty space in your tank, the gasoline will emit fewer fumes, and you’ll see more bang for your buck.”

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Stop car theme. Shoe press break car pedal

Power Braking

“Power braking is one of the worst things you can do for an automatic transmission car,” explains Christopher Grozdon, Co-founder and CMO of DASH-SEO. “It’s basically fully pressing the brake first and then pressing the accelerator simultaneously until the wheels are about to budge. Then, releasing the brake causes an accelerated ‘launch’ of sorts.”

This can be a bravado-infused “rev” of your car—a big no-no—but a less aggressive version of it can also be a common safety measure. You may have learned, perhaps even in driving school, a way to prevent your car from rolling backward when you’re braked on a hill and start moving again. It’s to do exactly that: With your foot still on the brake, hit the gas as well so that when your car starts moving, it’s moving forward.

But, unfortunately, doing this can harm the transmission, engine, and even the brakes. Instead of using a “power braking” method, Grozdon recommends twisting your wheels to the left or right, as you would when parking on a hill, to keep your car from rolling backward too far. Brush up a little more on some things you’ve probably forgotten since driving school.

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Close-Up Of Hand holding pressure gauge for car tyre pressure measurement
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Letting Tire Pressure Get Too Low

Understanding how tire pressure works can toe the boundary into confusing car jargon. But unfortunate consequences still result from neglecting this important car feature. And keeping an eye on does not present too much of a challenge; in fact, Reina calls it “one of the easiest and cheapest checks to perform.”

“Check your vehicle’s suggested pressure for each tire—check the exact numbers on the tire pressure label, usually found in the driver’s door jamb,” he advises. One thing he stresses is that you should be doing this “check” after your car hasn’t been driven for a little while, to avoid an inaccurate reading from the heat and friction created by driving.

Here’s how to check your tire pressure with a digital tire pressure gauge (video included). Buy one here.

In general, think about doing this check around once a month—don’t assume it’ll automatically be done when you get an oil change. And speaking of oil changes…

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Neglecting Oil Changes

Getting an oil change can be one of the most burdensome car repairs to stay on top of, especially since it needs to be done fairly frequently compared to many others. But don’t neglect it! Keep an eye on your car’s oil level.

“The car’s oil ensures that all parts of your engine run smoothly, so it’s critical that its level is maintained and kept in order,” says Bryan Rodgers, Owner of Rodgers Performance, a top dealer-alternative Audi repair and service specialist.

Experts recommend consulting your mechanic, and/or your car’s manual, to get a good idea of how often you actually need an oil change, and then set yourself a reminder—that you’re going to acknowledge—accordingly.

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Driving Woman
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Driving Light on the Gas Pedal

OK…weren’t we just saying not to ram the pedal too hard?! Yes, but there’s a difference between aggressively “flooring it” and putting an adequate amount of pressure on the pedal.

“Engines are made to be driven,” says Trotta. “Always [being] light on the gas pedal, trying to ‘save’ the engine…will cause carbon build up in the combustion chamber. The engine needs to be pushed a bit harder on occasion to help clear these deposits.”

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Car Wash
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Going Through Car Washes

Again…this is another one that requires a balance. Washing your car is of paramount importance, of course. But recently, car pros have become disenchanted with the automated car washes, pondering whether they do more harm than good—we even weighed in.

Roslyn McKenna, car insurance publisher for Finder.com, reports that “the bristles on the automated car washes can damage your car’s paint or even take off a windshield wiper.” So what does she recommend instead?

“Wash it by hand with a non abrasive cloth and soap designed not to damage paint.”

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Car under a protective cover parked on the roadside in the city
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Driving It Rarely

Of course, sometimes letting your car sit dormant is unavoidable—if you go on vacation, for instance. But as a general rule, you should take your car for a spin at least once a week.

“If your…car is left sitting in the driveway for a few months, the battery could die, the tires could deflate, parts could rust, and the fluids could dry up,” warns McKenna.

To keep your rarely-driven car from entering this potentially dangerous “dormant mode,” “make sure you’re taking [it] for a spin once a week for at least 15–30 minutes to keep it in tune and burn off the engine condensation,” McKenna says.

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car manual

Not Reading the Manual

There … you probably just rolled your eyes. Who has time to read a car’s entire manual?! And Rodgers even acknowledges this: “Drivers also need to read the car manual. Nobody ever does, but there are actually many useful tips in it,” he says.

“If you read your car manual, you’ll have a better idea of what to do and what not to do, as well as what to check and what to change regularly.”

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Altering Factory Settings

If it ain’t broke, don’t fix it. This is what Darryl Keckler, service director at Wilson County Motors, advises when he tells people not to add anything to their cars that will alter the factory settings.

This can include everything from “a computer chip to increase power” to widgets supposedly offering better fuel economy to a security system or remote starting feature that will mess with the factory settings.

You bought a car because you preferred that car, so don’t go Frankenstein-ing it with features that it doesn’t have.

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Modern automotive wheel on alloy disc

Mixing and Matching Tires

If you use tires of differing sizes or brands on the same car, you might get more than you bargained for. “Doing so will affect more than just the ride,” Keckler told RD.com.

It changes ABS operations [and] it changes speedometer and wheel sensor operations.” And you definitely want all of those things to be working! You can imagine how quickly an inaccurate speedometer could get you into trouble.

Reader's Digest
Originally Published on Reader's Digest