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

Failing to check the brake pads for wear can lead to bigger and more expensive repairs later on, including the brake drums or rotors.

Using the shifter as a hand rest is frowned upon for a few reasons. Let's talk safety, first. With only one hand on the steering wheel, you're not able to make sudden steering corrections or maneuvers, if needed. And then there's what it does to your vehicle. Your resting weight on the lever strains parts of your car's transmission, including the bushings and synchronizers, and leads to general premature wear on the gear teeth.

You can expect most car batteries to last about five years. Beyond that, the acid of the old battery may do some damage, including corroding the battery terminals and the cables that connect with the battery posts, as well as damaging the strap holding the battery in place.

For the longest-lasting, all-around good general tire, consider all-seasons. Consumer Reports testing has found the best all-seasons can last for almost 100,000 miles, while the worst can need replacing after 55,000 miles.

Using the wrong oil may not seem like a big deal. Engine oil lubricates, so any oil is good, right? Not exactly. While it's true a lubricated engine is a well-running engine, using the wrong oil viscosity (its thickness) is a big deal. It may not lubricate as well as it should, which can shorten the life of your car's engine. Stick with the viscosity recommended by your car's manufacturer, found in the owner's manual.

The heavier your vehicle is, the more stress it puts on parts such as the brakes, drivetrain and suspension. And more weight also means it'll use more fuel. Additionally, carrying too much weight on your car may affect its braking, handling, stability, towing capacity and rollover resistance. In extreme cases, you could damage the transmission -- especially going uphill -- damage the suspension, cause structural damage or even blow the tires.

Sudden stops, and quick acceleration, can cause a few problems. Not only will it cause your gas mileage to take a nosedive, it can also cause wear on parts including brake pads and rotors. Both habits can damage drivetrain components like engine and transmission mounts, as well.

You hear an occasional knock or an intermittent squeak or feel an odd new vibration. It could be superficial, and therefore no big deal, but it could be an early warning sign that something is going wrong. Neglecting minor symptoms can mean big bills -- and maybe a tow truck -- later.

This is a true story, actually. A fuel delivery service accidentally filled a pump with jet fuel at a gas station in New Jersey. The cars that had filled up on the kerosene didn't perform better. In fact, because auto engines can't combust (burn) this fuel, they all stalled.

Skipping them, or just not doing any (yikes!), will at first cause your car's engine to run less efficiently, but over time that's not all. Without proper lubrication, the components of your car's engine will warp and wear out, leading to catastrophic failure. The concept of doing an oil change every three months or 3,000 miles is a bit outdated, but your car does need to have regular oil changes. For many modern cars the interval is often every 5,000 miles, but you'll need to read your car's owner's manual for its recommended interval (and type of oil).

If 87 Regular is suitable for your vehicle, there's no need to fill up with Plus or Premium grades in an effort to give it a treat. Octane ratings don't work that way. The ratings measure how well the fuel mixture can withstand pre-ignition knocking -- high-performance engines will perform better with higher octane.

Riding your brakes, whether it's downhill or as a bad habit, can cause excessive wear and tear on your car's brake pads and rotors, causing them to warp. Remember, too, the decompression that's occuring in the car's drivetrain will help keep your car's speed in check. Instead of riding your brakes to keep your car from going too fast, try shifting into a lower gear.

For the smoothest ride, best traction and steering control, and least wear and tear on your tires, it's important to have your tires balanced. Unbalanced tires can cause poor gas mileage and rough vibrations that you feel in the cabin. Plus, in addition to putting unnecessary stress on the car's bearings, shocks, and wheel assembly, you'll see uneven wear on your car's tires.

A lot of car owners admit they skip oil changes. But what about changing your car's intake air filter? We don't mean the one that filters the cabin air. We mean the one that filters the air before it enters your car's engine. It's important because the dirtier the filter is, the more it can restrict air flow to the engine, which, at first robs the engine of power, and then eventually causes the engine to overheat. Maintenance schedules vary depending on the car, so check the owner's manual for the recommended interval for your car.

Although you can expect many modern coolants to last for 5 years or 50,000 miles, most experts stand by just one rule here: if you take the cap off your car's radiator, peek in and see that the coolant looks dirty and brown, it's time for a change. Depending on your car and on driving conditions, that could be every two years, as some mechanics recommend.

Did you know that the pressure in your tires is reduced by one pound per square inch (PSI) for every 10-degree drop in the air temperature? And they also lose up to one PSI every month, so it's good to check them about every 30 days. It'll help not only the handling, but also your gas mileage. You'll know your tires are properly inflated if they each match the PSI found on the sticker inside the driver’s door of the vehicle (or in the owner's manual).

The parking brake may not seem like it does much -- after all, the car's in 'Park' -- but when it's engaged, it will hold your car in place better than 'Park' alone. Not using it in a car with an automatic transmission does make a difference, and can take years off the life of your transmission's components. And, it is also true that without regular use, the cables for the parking brake, which are under the car, can corrode or break.

This is one of those things where some people argue it's best to warm a car up -- which means you're bringing the engine and all the fluids up to temperature -- before driving it, and others believe it's no longer necessary in new cars. However, there's no need to let it idle for awhile. Give it about 30 seconds to loosen up before you go.

Topping off your fuel tank may seem like no big deal -- hey, more fuel! But, it can actually cause your car to run poorly, it may even damage the engine, and it's definitely not good for the environment. Additionally, modern fuel pumps have vapor-recovery systems, which don't allow extra fuel to go into your tank. That extra gas you think you're getting is actually fed right back into the gas station's tanks, although you're paying for the top off.

While your car's engine doesn't mind a warm garage in the cold winter weather, the exterior of your car begs to differ. A car that's been out in the elements -- snow, ice, and the chemicals used to treat the wintery roads -- and is kept in a heated space has an increased risk of developing exterior rust. Parking in a garage or covered space is fine, just make it one that's not temperature-controlled.

An engine's cylinder contains air and fuel. Air is compressible, so when the piston squeezes it, the pressure goes up. Water, however, is not compressible, and if it's in your engine's cylinders when the piston tries to squeeze, things break -- known as a hydrolocked engine. It can happen, for some cars, in just a few inches of water.

Hot, sunny days may seem ideal for a car wash, but when the water and soap meet the heat of your car's exterior you won't be able to keep up with how fast the droplets dry -- and that means residue. This soapy, grimy residue doesn't just give your car a dull appearance, it also leaves it at risk for paint damage. For the spotless finish you're looking for, a party cloudy or overcast day between 60 and 80 degrees Farhienent is ideal for washing and waxing your car. And if it's always hot and sunny, move into the shade before you begin, or wash and wax early in the morning or in the evening.

Never, ever, pour hot water on an icy windshield, unless you're in the market for a new windshield. the hot water will shatter an ice-cold windshield. The best way to remove snow and ice from your car's windshield is with its defroster, on full blast, and an ice scraper with a little elbow grease. Spraying a mixture that's two parts 70 percent isopropyl alcohol and one part water will also do the trick.

Pressure washing your car's engine will get it clean, that's for sure -- but it may not run afterward. The preferred way to clean an engine used to be to steam clean it, but today's safe cleaning includes a degreaser and a regular ol' garden hose. Both are improvements over shooting jets of water in and around all those seals and hoses and electrical parts.

A 2009 study by AAA found more than 50 percent of all motorists are following the wrong maintenance schedule. If you tend to drive in hot or freezing (extreme) temperatures, if you drive in stop-and-go traffic or at speeds less than 50 mph for long distances or if you tow a trailer or use your car's roof rack you should be following the "severe" schedule. Also considered severe? Frequent driving on roads that are dusty, muddy or spread with loose gravel, driving in mountainous areas and extensive braking.

Did you know dirt can hurt your ride? It can wear down your car's paint job, and when your car's paint gets compromised it sets the stage for rust. And rust is the flesh-eating bacteria of vehicles. Some experts will say a weekly wash is best. If that seems like a lot, just try to keep it clean. And don't forget to wax. It adds a protective barrier between the paint and the world.

Whether you call it the malfunction indicator lamp, the check engine light or the service-engine-soon light, when it comes on, don't ignore it. It could be minor like a loose gas cap or a major engine problem, but you won't know until you take it to a mechanic. When it illuminates it indicates there's a problem with your car's computerized engine-management system. The longer you wait to get that check engine light checked, the more likely you are to cause serious damage to your car.

Shifting suddenly from reverse into drive without stopping between isn't going to cause your engine to seize or your transmission to fail today. But continue this driving habit over time and you'll do damage to your car's drivetrain: that's the transmission, differential and drive shafts.

In order for your car's air conditioning to work properly, it needs a refrigerant. Over time, that refrigerant can leak through the seals, but you won't know it's happening until the day you notice the air conditioning system isn't blowing cold air through the vents. To restore it, the unit needs a recharge. And while refrigerant leaks are common, the AC may also fail from a fan not working or a faulty compressor.

Generic tune-ups aren't really needed on modern cars with on-board computers. However, following the suggested preventative maintenance for your car -- look in your car's owner's manual for its schedule -- is always recommended.

It sounds like a good idea -- your car's engine is getting old and tired and an oil additive will rejuvenate it. Except it won't, and the Federal Trade Commission has targeted companies selling the products for false advertising claims.

It's convenient to keep the clutch engaged when you're stopped -- you can quickly inch forward in stop-and-go traffic, or take off at a green light. However, your car likely thinks it's inconvenient. Keeping it engaged this way can cause premature wear, and it can also damage parts of the clutch system, like the release arm or the pressure plate. Better to keep it in neutral with the clutch out until it's time to go.

It's normal wear and tear on your car's suspension and can happen as easily as when you bump a curb while parking. You'll notice your car pulls to the left or right while you're driving. Or you may notice the steering wheel vibrates, or it's crooked although you're driving straight. And, in addition to these, when your car is out of alignment the tires will, also, wear unevenly. Having your car aligned when you see these signs can save you money on tires and gas, and will also keep your ride safer.

It may seem pretty harmless, but adding only a few gallons of gas at a time or regularly running with your tank a quarter full or less can damage your car. There are two common problems that can happen when you do this. One, there isn't enough fuel in the tank to keep the fuel pump submerged, and many pumps rely on that to keep from getting too hot. And, two, gunk. If the fuel level isn't very high, it forces the system to pump gas from the bottom of the tank -- and that's where sediment naturally builds up. That sediment can clog your car's fuel filter, and it can damage the engine.

Hard acceleration, and the hard braking that follows, is hard on your car's drivetrain and on its braking components. Safety aside, indulging in this can add a lot of extra wear and a lot of additional repairs.