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9 Bad Habits That Could Damage Your Car

Mechanics say drivers should stop doing these things to extend vehicle life

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​If you’ve been driving for years, chances are you’ve had to bring your car to a service station for repairs — maybe expensive ones. These costly repairs go well beyond basic car maintenance, and they’re often the result of bad habits drivers may not know they have. We asked mechanics to share some of the most common things drivers do that can damage a car’s engine, transmission, brakes and other vital automotive components.

Here are some bad habits to avoid:

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1. Avoiding routine maintenance

On today’s cars, delaying oil changes causes carbon buildup, says Frank Leutz, founder of Desert Car Care in Chandler, Arizona, who hosts the Wrench Nation Car Talk radio show and podcast.

Leutz describes carbon as a “black, broccoli-like substance” that is a by-product of engine oil and gas. “Over time, if this carbon builds up from the lack of oil changes or the lack of fuel system treatments to clean it, that carbon will destroy miles per gallon and introduce subtle but annoying hesitations like hard starts,” he says. Leutz says he has seen cars that need expensive repairs due to carbon buildup on engine valves.

Putting off an oil change for 1,000 miles after it’s recommended can damage car components, says Demeny Pollitt, owner of Girlington Garage in South Burlington, Vermont.

“Oil serves as a barrier between two metal pieces to keep them from rubbing against each other,” she says. If you wait too long, the oil starts to break down.

“Then, that barrier is no longer effective; there’s metal-on-metal contact that can wear it down and send more metal through the system” Pollitt says.

2. Ignoring strange noises

Generally, if a vehicle is in tip-top shape, drivers shouldn’t hear any screeching, clunking or grinding noises.

“I wish people would stop ignoring the sounds their car is making,” says Andrea Dello Russo Campbell, owner of Andrea’s Auto, a repair shop in Edgartown, Massachusetts.​

“That little squeak is an indicator, so don’t just turn the radio up and ignore it, because the squeak becomes a grind, and the grind becomes a problem,” she says. “Then, it just gets more expensive the louder the noise gets.”

Leutz adds that noises can be related to safety issues: A clunking sound might mean a suspension problem, while a loud screech could mean a failing fuel pump. If you hear rumbling, it could mean your wheel bearing is too worn, and a grinding sound may indicate brake issues.

3. Ignoring odd smells

Think you smell something burning? Don’t assume it’s nothing, Pollitt says.

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“Even if it goes away, it’s not going away forever,” she says. “You know your car better than anyone else does. If there’s a new smell, you should definitely have it checked out.”

Oily, burning odors could mean fluids are leaking onto your engine or exhaust, while the smell of burning rubber might mean a failing drive-belt system, which could result in a car’s engine overheating.

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4. Not noticing warning lights

Many drivers see a “check engine” light pop up on their dashboard and assume that if their car seems to be working fine, the light will eventually go away on its own.

“That’s not the case,” says Leutz, who notes that many transmission or engine issues won’t cause obvious symptoms — at least at first — while driving.

In other words, “any light coming on is a warning,” he says. “Take care of it immediately, or it could end up costing big money down the road.”

5. Shifting gears before coming to a full stop

Switching between drive, reverse or park when your vehicle is moving is never recommended, says Pollitt. “It definitely wears out your transmission a lot faster,” she notes.

Leutz recommends smooth, controlled shifting into reverse, especially with a stick shift.

“The vehicle is still settling in from its last state of transmission shift point, and not allowing the transmission to catch up with the engine can damage gears and shift levers,” he says. “It’s important to take your time.”

6. Driving on worn, underinflated or unbalanced tires

Some drivers notice when the tire pressure light comes on but decide the tires look fine. Or they notice a tire is low but drive on it anyway, Pollitt says. “When you drive on a tire that’s low, it destroys the sidewall inside,” she says. “You can’t see from the outside that there’s a problem, but the inside of the tire has started crumbling — it’s almost like black rice inside.”

Getting a patch or a plug to repair your tire runs about $30 to $60, while replacements cost $80 to $250 per tire, plus labor, she adds.

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Pollitt also says many drivers fail to pay attention to their tires’ tread depth.

“People don’t listen when we say, ‘You should get new tires.’ It’s just so dangerous. Your tires are the only parts of your car that touch the ground, so it’s important to have good tires,” she says.

If you buy a used car, always check the year the tires were manufactured, adds Leutz. If they’re older than five years, replace them — even if they look brand new — because the rubber breaks down over time. And don’t forget to get your tires rotated and balanced every six months to maintain their life.

7. Ignoring manufacturers’ recall notices

Even if your car’s running well, always open recall notices sent by the manufacturer, Leutz says. If you’ve moved recently, keep up to date by visiting the National Highway Traffic Safety Administration’s recall page and typing in your vehicle identification number.

“These recalls are imperative because they have all to do with the safety and reliability of the vehicle,” Leutz says.

8. Failing to notice wet, oily stains under your car

See a puddle underneath your car? It’s time to have a mechanic check it out, Dello Russo says. “If it’s the wrong kind of fluid leaking out of your car, like engine oil, that will kill your whole car,” she says.

Oily stains might also mean your power steering, brake system or transmission is leaking. Having low fluid levels can lead to early engine or transmission failure, and if you don’t have enough brake fluid, brakes won’t work properly.

9. Bringing your own car parts to a garage

Drivers may want to save a few bucks by purchasing their own car parts, but just as you’d never bring a dozen eggs to a restaurant, don’t show up with your own supplies at a service center either, says Dello Russo.

“First, there’s no warranty, so if those brake pads are made out of non-reliable material, they can wear through in 10,000 miles versus 60,000 miles,” she says. “Also, you don’t know where these parts are from. I can reliably get parts from sources I trust as a mechanic, which makes it easier for you to trust me when I put these parts in your car.”

What’s more, you’re probably bringing in the wrong part, Leutz says. Many repair shops will not provide a warranty on work with a client-supplied part: “It’s critical to allow a parts-and-labor service experience so that you’re protected in the end fully if something were to go wrong,” he says.

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