Should You Know About Muffler Rattling

am3A loose bracket, rubber hanger or connector, or one that is badly corroded, can allow a muffler to rattle when you accelerate or drive on bumpy roads, or even when the car is stationary and idling.

A loose muffler can allow excessive movement in other components as well and increase the stress on those parts, so it can become more than an annoying noise if left unattended. If the muffler is hanging lower than normal, there’s also a risk that it could be broken off by hitting a bump or going over railroad tracks.

Modern exhaust systems are usually made of aluminized steel or stainless steel, but that doesn’t mean they or the parts that hold the exhaust components in place last forever. Heat, debris, road salt and moisture can all cause rust in the exhaust system.

Though a muffler rattle might be fixed simply by tightening a couple of bolts or replacing a broken hanger, the corrosion might be bad enough on the muffler or neighboring parts that they will have to be replaced.

A rattle or banging noise from the exhaust system might not be an external problem. Baffles or other components inside of mufflers can come loose and cause internal rattles.

In addition, the muffler may not be the only cause or even the culprit. Brackets and bolts securing tailpipes, heat shields above catalytic converters and other components can come loose, and catalytic converters can develop internal rattles when they go bad.

All Information About Air Conditioner Condenser

am2The air-conditioning condenser is a radiator positioned between the car’s grille and the engine-cooling radiator in which the gaseous refrigerant sheds heat and returns to a liquid state. The liquid refrigerant flows to the evaporator inside the dashboard, where it cools the cabin. Is your car not cool enough for you, at least temperature-wise? It might result from a clogged air-conditioning condenser or disabled cooling fan. A leak in the condenser also will result in a loss of refrigerant.
How do I know if my air-conditioning condenser has gone bad?
Well, it’ll be warmer than you want, or your windows will be foggy. If refrigerant leaks, the air conditioner won’t spit out much cold air, if any. Leaks can be located by adding an ultraviolet dye to the refrigerant. Air-conditioning output also can be diminished by crud that builds up on the front of the condenser, and cleaning the condenser may restore some performance.

How often should I replace my air-conditioning condenser?
As with other parts of the air-conditioning system, the condenser generally doesn’t need servicing as long as the system is producing cold air. Some mechanics recommend periodically inspecting the condenser for signs of damage or corrosion and doing an external cleaning or internal flush if needed.

Why do I have to replace my air-conditioning condenser?
Because it’s an integral part of your air-conditioning system, and you won’t be comfortable, or be able to see, if it’s broken. Some condensers can be cleaned externally with a hose, and others can be cleared of sludge with an internal flush, but many mechanics recommend replacing a condenser that is clogged or corroded.

Know More About Condition of Your Tires

am1In February 2008, the owner of a 1998 Ford Explorer in Georgia needed a new tire for his SUV and ended up buying a used one. When he was driving two weeks later, the tread suddenly separated from the tire. The Explorer went out of control and hit a motorcycle, killing its rider. An analysis of the used tire revealed that it was nearly 10 years old.

More recently, an investigation into the cause of the accident that killed the actor Paul Walker revealed that the Porsche Carrera GT in which he was riding had nine-year-old tires. The California Highway Patrol noted that the tires’ age might have compromised their drivability and handling characteristics, according to the Los Angeles Times.

These incidents illustrate not only the potential danger of buying used tires but also the perils of driving on aging tires — including those that have never spent a day on the road.

For years, people have relied on a tire’s tread depth to determine its condition. But the rubber compounds in a tire deteriorate with time, regardless of the condition of the tread. An old tire poses a safety hazard.

For some people, old tires might never be an issue. If you drive a typical number of miles, somewhere around 12,000-15,000 miles annually, a tire’s tread will wear out in three to four years, long before the rubber compound does. But if you only drive 6,000 miles a year, or have a car that you only drive on weekends, aging tires could be an issue. The age warning also applies to spare tires and “new” tires that have never been used but are old.

What Happens to a Tire as It Ages?
Sean Kane, president of Safety Research & Strategies, Inc., compares an aging tire to an old rubber band. “If you take a rubber band that’s been sitting around a long time and stretch it, you will start to see cracks in the rubber,” says Kane, whose organization is involved in research, analysis and advocacy on safety matters for the public and clients including attorneys, engineering firms, supplier companies, media and government.

That’s essentially what happens to a tire that’s put on a vehicle and driven. Cracks in the rubber begin to develop over time. They may appear on the surface and inside the tire as well. This cracking can eventually cause the steel belts in the tread to separate from the rest of the tire. An animation on the Safety Research & Strategies Web site shows how this happens. Improper maintenance and heat accelerate the process.

Every tire that’s on the road long enough will succumb to age. Tires that are rated for higher mileage have “anti-ozinant” chemical compounds built into the rubber that will slow the aging process, but nothing stops the effects of time on rubber, says Doug Gervin, Michelin’s director of product marketing for passenger cars and light trucks.

How Long Does a Tire Last?
Carmakers, tire makers and rubber manufacturers differ in their opinions about the lifespan of a tire. The National Highway Traffic Safety Administration (NHTSA) has no specific guidelines on tire aging and defers to the recommendations of carmakers and tire manufacturers. Carmakers such as Nissan and Mercedes-Benz tell consumers to replace tires six years after their production date, regardless of tread life. Tire manufacturers such as Continental and Michelin say a tire can last up to 10 years, provided you get annual tire inspections after the fifth year.

The Rubber Manufacturers Association says there is no way to put a date on when a tire “expires,” because such factors as heat, storage and conditions of use can dramatically reduce the life of a tire. Here’s more on each of these factors.

Heat: NHTSA research has found that tires age more quickly in warmer climates. NHTSA also found that environmental conditions like exposure to sunlight and coastal climates can hasten the aging process. People who live in warm weather and coastal states should keep this in mind when deciding whether they should retire a tire.

Storage: This applies to spare tires and tires that are sitting in a garage or shop. Consider how a spare tire lives its life. If you own a truck, the spare may be mounted underneath the vehicle, exposed to dirt and the elements.

If your spare is in the trunk, it’s as if it is “baking in a miniature oven,” says Dan Zielinski, senior vice president of public affairs for the Rubber Manufacturers Association. Most often, the spare never sees the light of day. But if the tire has been inflated and mounted on a wheel, it is technically “in service,” even if it’s never been used, Gervin says.

A tire that has not been mounted and is just sitting in a tire shop or your garage will age more slowly than one that has been put into service on a car. But it ages nonetheless.

Conditions of use: This refers to how the tire is treated. Is it properly inflated? Has it hit the curb too many times? Has it ever been repaired for a puncture? Tires on a car that’s only driven on the weekends will have a different aging pattern than those on a car that’s driven daily on the highway. All these factors contribute to how quickly or slowly a tire wears out.

Proper maintenance is the best thing a person can do to ensure a long tire life. Gervin recommends that you maintain proper air pressure in tires, have them rotated regularly and have them routinely inspected.

How To Determine the Age of a Tire
The sidewall of a tire is full of numbers and letters. They all mean something, but deciphering them can be a challenge. This Edmunds article about reading a tire’s sidewall goes into greater detail, but for the purposes of determining the age of a tire, you’ll just need to know its U.S. Department of Transportation (DOT) number.

Tires made after 2000 have a four-digit DOT code. The first two numbers represent the week in which the tire was made. The second two represent the year. A tire with a DOT code of 1109 was made in the 11th week of 2009. Tires with a three-digit code were made prior to 2000 and are trickier to decode. The first two digits still tell you the week, but the third digit tells you the year in the decade that it was created. The hard part is knowing what decade that was. Some tires made in the 1990s (but not all) have a triangle after the DOT code, denoting that decade. But for tires without that, a code of “328” could be from the 32nd week of 1988 — or 1978.

Clearly, these DOT numbers weren’t designed with the consumer in mind. They were originally put on tires to make it easier for NHTSA to recall tires and keep track of their manufacturing date.

To make matters worse, you might not always find the DOT number on the outer side of the tire. Because of the way a tire is made, it is actually safer for the technician operating the mold to imprint information on the inner side of the tire, so some manufacturers will opt to put the number there. It is still possible to check the DOT code, but you might have to jack the car up to see it. Keep the visibility of the DOT number in mind the next time you are at a tire shop and the installer asks if you want the tires to be mounted with the raised lettering facing in.

That potential inconvenience is going away, however. NHTSA says that the sidewall information about the tire’s date of manufacture, size and other pertinent data is now required to be on both sides of the tire for easier reading.

After checking out a tire’s birth date, give the rubber a visual inspection. Some of the best advice on such an inspection comes from the British Tyre Manufacturers’ Association. It recommends that consumers check tires regularly for any sign of aging, such as tread distortion or large or small hairline cracks in the sidewall. Vibrations or a change in the dynamic properties of the tire could also be an indicator of aging problems, the association says. It recommends replacing the tire immediately if such symptoms appear.

Don’t Buy Used
Tires are expensive, especially when you factor in the price of mounting and balancing. That’s why used tires become more attractive to consumers who are strapped for cash. But the purchase of used tires is very much a buyer-beware situation, Zielinski says. “Even a one-year-old tire can be dangerous if it was poorly maintained,” he says.

When a consumer buys a used tire, he has no idea how well it was maintained or the conditions in which it has been used. The previous owner might have driven it with low pressure. It could have hit curbs repeatedly. It could have been patched for a nail. Further, it’s a dated product.

“You wouldn’t want a used tire for the same reason that you wouldn’t buy a 10-year-old computer,” Zielinski says. “You are denying yourself the advancements in tire technology over the past few years.”

Make Sure You’re Getting a “Fresh” Tire
Just because a tire is unused doesn’t mean it’s new. In a number of instances, consumers have purchased “new” tires at retail stores only to find out later that they were manufactured years earlier. In addition to having a shorter life on the road, a tire that’s supposedly new but is actually old may be past its warranty period.

If you buy tires and soon after discover that they’re actually a few years old, you have the right to request newer ones, Zielinski says. Any reputable store should be willing to make amends. “It is fair for a consumer to expect that ‘new’ is not several years old,” he says.

Letting Go
Getting rid of an unused spare or a tire with good-looking tread may be the hardest thing for a thrifty consumer to do. “Nobody’s going to take a tire that looks like it’s never been used and throw it out,” Kane says. But if it’s old, that’s exactly what the owner should do.

Although Kane has lobbied NHTSA to enact regulations on tire aging, nothing is currently on the books. A NHTSA spokesman says the organization is “continuing to conduct research into the effects of tire aging, and what actions consumers can do to safely monitor their tires when they are on their vehicles.”

It’s too bad that tires don’t have a “sell by” date, like cartons of milk. Since there’s no consensus from government or industry sources, we’ll just say that if your tire has plenty of tread left but is nearing the five-year mark, it’s time to get it inspected for signs of aging.

Of all your vehicle’s components, tires have the greatest effect on the way it handles and brakes. So if the tire store recommends new tires at your five-year check-up, spend the money and don’t put it off. Your life could depend on it.

Let’s Learn How Often Should Replace an Accessory Drive Belt

Most vehicles have a rubber belt on the front of the engine that drives accessories such as the air-conditioning compressor, power steering pump and alternator. If this accessory drive belt (also called a V or serpentine belt) breaks, the battery won’t get charged, the air conditioner won’t blow cold air and the power steering will go out. In addition, if the belt drives the water pump, the engine could overheat.

Most manufacturers call for periodic inspection of the belt as part of scheduled maintenance, but few list a specific replacement interval, and inspection intervals vary widely.
Mercedes-Benz, for example, says to inspect the belt every two years or 20,000 miles, while Volkswagen says to check it every 40,000 miles. On most Ford vehicles, the manufacturer says to start inspecting it after 100,000 miles and then every 10,000 miles. On many GM vehicles, the first recommended inspection is at 150,000 miles or 10 years.

Though these belts often last many years, they can become cracked or frayed and need to be replaced. That’s why they should be inspected at least annually on vehicles that are more than a few years old. In addition, if a belt needs to be replaced, the pulleys and tensioners that guide the belt should be inspected to determine if they caused damage other than normal wear.

A belt that isn’t cracked or frayed may look like it’s in good shape, but grooves on the hidden side may be worn enough that the belt slips on the pulleys that drive the accessories. That will cause problems in systems that rely on the belt to keep things humming. For example, a slipping drive belt may cause the alternator to work intermittently or at reduced power, and the battery won’t get fully recharged as a result, perhaps triggering a warning light.

Another sign of a worn belt is a squealing noise under acceleration. That could indicate that the belt is slipping because of wear, a belt tensioner is loose or a pulley is out of alignment.

Most modern vehicles use belts made from ethylene propylene diene monomer, a synthetic rubber that lasts longer than older types of engine belts. Most belt manufacturers estimate the typical lifespan of an EPDM belt to be 50,000 to 60,000 miles, and some say it’s more than 100,000 miles. However, it can be hard to tell how worn one is with just a visual check because EPDM belts are less likely to crack or lose chunks of rubber than other types. They should be inspected by a professional.

Information About How Long Does a Car Battery in a New Car Last

Though battery problems are often associated with cold weather, Consumer Reports magazine says heat is a bigger enemy of car batteries and will take a bigger toll on performance and reserve capacity. The magazine recommends that vehicle owners in hotter parts of the country have their car battery tested after two years of ownership and then every year after. Those who live in colder areas can wait four years to test performance and capacity, and then every year after.

“Heat kills batteries,” according to John Banta, a Consumer Reports project leader and part of the team that tests batteries for the magazine. “Many times in cold climates your battery fails to start your car on a below-freezing day. The reason this happens is that the heat of the past summers has weakened your battery. When you use it in the cold, the starter requires more electrical current to turn over the cold engine with its thickened oil.”

Testing a battery’s performance and reserve (or amp-hour) capacity is not just a matter of seeing whether it will hold a charge (or checking the electric eye found on some batteries to see if it is green), so testing is best done by an auto technician.

Know More About How Often Should Tires Be Balanced

Smooth driving is a balancing act that requires getting the wheels and tires to rotate at high speeds without vibrations. That’s not a slam dunk; a dirty little secret about wheels and tires is that they usually aren’t perfectly round, even when brand new. What’s more, their weight often isn’t evenly distributed, so they’re heavier in some spots than others.
Either issue can cause annoying vibrations. Out-of-balance tires can also cause rapid tire or suspension wear, so it’s not just about ride comfort.

That is why when new tires are mounted on wheels they’re spin-balanced to detect vibrations. Some vibrations can be eliminated by rotating the tire on the wheel so the heavy or “high” spot is in a different location that better matches up with the wheel. Small weights are attached to the wheels with adhesives or clips to counteract the heavy spots and provide a smooth ride. Over time, though, the weights can fall off. If that happens to a front wheel, you may feel vibrations through the steering wheel that typically become more pronounced as vehicle speed increases.

Many tire dealers include free lifetime rotation and balancing with new tires (something you should ask about before buying). Tire rotation is when the vehicle’s tires are removed and reattached at a different position to ensure they wear evenly, which should be done every 5,000 to 7,500 miles on most vehicles, or according to the automaker’s recommendation.

Many consumers neglect the balancing part and have their tires rotated only periodically. If balancing was included with the tires, it would be wise to remind the shop to check the balance at the same time. Even if balancing costs extra, it’s a good idea to have it checked at least every two years, or more often in areas where roads are not well-maintained.

Vibrations can also be caused by a bent wheel, a damaged tire (which won’t be fixed by balancing), worn suspension parts or worn wheel bearings, so balancing the wheels and tires may not eliminate all vibrations.

Tires and wheels are balanced before being attached to the vehicle by spinning them on a balancing machine that identifies heavier or stiffer spots that cause vibrations. Some tire dealers and repair shops use “road force” balancing machines that simulate the weight and forces applied to tires and wheels during driving conditions. They say this method provides more accurate and detailed readings that allow more precise balancing.

More Information About Brakes Squealing

If you’re lucky, the squealing (or squeaking) noise that your brakes make when you first drive your car in the morning, particularly after rain or snow, is just surface rust being scraped off the rotors by the pads the first few times you apply the brake pedal, or the result of moisture and dirt that collects on the rotors, including from condensation caused by high humidity. If it goes away after a few brake applications, no worries.

If the noise persists most times or every time you apply the brakes or stays on continuously while you’re driving, the cause is more serious — and the fix will be more expensive.

A continuous high-pitched squeal while you’re driving is usually the sound of a built-in wear indicator telling you that it’s time for new pads. As the pads wear down and get thinner, a small metal tab contacts the rotor like a needle on a vinyl record to warn you it’s time for new pads. (Some wear indicators may work differently and engage only when you apply the brakes.)

Other squeals and squeaks will require a brake inspection to diagnose, and may require cleaning, lubrication or adjustment, and possibly new parts. Most brake noise is caused by worn or loose parts.

For example, an unevenly worn rotor (often referred to as “warped”) won’t let the brake pads press flat against the rotor when you apply the brakes, and that can create vibrations that generate noise. Likewise, an unevenly worn pad won’t press tightly against the rotor and may chirp. Another possibility is that the pads are loosely mounted, or the shims that hold them in place have corroded or become loose.
And then there are the pads themselves. Some mechanics warn that bargain-bin pads are more likely to be noisier than higher-quality, more-expensive pads. In addition, loose or sticking calipers can contribute noise.

Because there are several possibilities, and because brakes are a crucial safety feature, it is best to have a pro diagnose noise.

A grinding sound usually means that the pads have worn away, and now the backing plates on which they were mounted are being squeezed against the rotor. This metal-to-metal contact means that you will need to replace the rotor as well — and that you probably ignored some earlier warning signs of brake wear.

When The Best Time You Should Change Engine Coolant

For some vehicles, you’re advised to change the coolant every 30,000 miles. For others, changing the coolant isn’t even on the maintenance schedule.

For example, Hyundai says the coolant (what many refer to as “antifreeze”) in most of its models should be replaced after the first 60,000 miles, then every 30,000 miles after that. The interval is every 30,000 miles on some Mercedes-Benz models, but on others it’s 120,000 miles or 12 years. On still other Mercedes, it’s 150,000 miles or 15 years.

Some manufacturers recommend changing the coolant more often on vehicles subjected to “severe service,” such as frequent towing. The schedule for many Chevrolets, though, is to change it at 150,000 miles regardless of how the vehicle is driven.

Many service shops, though — including some at dealerships that sell cars with “lifetime” coolant — say you should do it more often than the maintenance schedule recommends, such as every 30,000 or 50,000 miles.

Here’s why: Most vehicles use long-life engine coolant (usually a 50/50 mixture of antifreeze and water) that for several years will provide protection against boiling in hot weather and freezing in cold weather, with little or no maintenance. Modern vehicles also have longer intervals between fluid changes of all types partly because environmental regulators have pressured automakers to reduce the amount of waste fluids that have to be disposed of or recycled.

Coolant can deteriorate over time and should be tested to see if it’s still good, as it can be hard to tell just by appearances. Even if testing shows the cooling and antifreeze protection are still adequate, antifreeze can become more acidic over time and lose its rust-inhibiting properties, causing corrosion.

Corrosion can damage the radiator, water pump, thermostat and other parts of the cooling system, so the coolant in a vehicle with more than about 50,000 miles should be tested periodically. That’s to look for signs of rust and to make sure it has sufficient cooling and boiling protection, even if the cooling system seems to be working properly. It can be checked with test strips that measure acidity, and with a hydrometer that measures freezing and boiling protection.

If the corrosion inhibitors have deteriorated, the coolant should be changed. The cooling system might also need to be flushed to remove contaminants no matter what the maintenance schedule calls for or how many miles are on the odometer. On the other hand, if testing shows the coolant is still doing its job and not allowing corrosion, changing it more often than what the manufacturer recommends could be a waste of money.

Know More About Some Radiator and Cooling System Problems

If steam is pouring from under your hood, a temperature warning light is glowing bright red on your dashboard or the needle in the temperature gauge is cozying up to the High mark, it’s time to pull off the road and shut down the engine before it fries from overheating.

Any indication of overheating is a serious matter, so the best course of action is to shut down the engine to prevent further damage. Driving a car with an overheated engine can warp cylinder heads and damage internal engine parts such as valves, camshafts and pistons.

Even letting the engine cool for an hour and topping off the radiator with a 50-50 mix of antifreeze and water may not fix what’s wrong. Here are some reasons an engine will overheat:

– The coolant level could be extremely low, because of long-term neglect or because a leak has developed in the radiator or radiator hoses. Coolant circulates inside the engine block to cool it, and the leak might be in the block, or from the water pump or heater hoses. Old coolant loses its corrosion-inhibiting properties, allowing rust to form and ultimately causing damage.
– The thermostat that allows coolant to circulate may be stuck in the closed position or a clog may have developed, perhaps from debris in the cooling system.
– The engine cooling fan has stopped working or the radiator’s cooling fins are clogged with debris so that the air flow that reduces the coolant temperature is restricted.
– The radiator cap has gone bad and no longer maintains enough pressure in the cooling system, allowing coolant to boil over (engines normally operate at about 210 to 220 degrees Fahrenheit).
– The head gasket that seals the gap between the cylinder head and engine block may have failed, allowing coolant to leak inside the combustion chambers. The steam should be visible coming out of the exhaust system.
– The water pump has stopped working or the belt that drives it broke or is slipping and not pumping enough coolant.
– You’ve been towing a 5,000-pound trailer with a vehicle equipped to tow only 2,000 pounds, exceeding the vehicle’s cooling capacity. (You probably also strained the transmission.)

Checking your engine coolant level in the overflow tank on a regular basis can help avoid disasters. If you have to keep topping off the coolant, that’s an indication of a small leak that should be taken care of before it becomes a major one. Having your coolant tested and the entire system inspected by a mechanic every couple of years is an even better way to prevent cooling system disasters.

Steps To Fix Your Car’s Oxygen Sensor

If your car’s “Check Engine” light is glaring at you, it’s probably because the oxygen sensor is malfunctioning. That’s right, the oxygen sensor. It’s a little device that’s a mystery for most drivers but its misbehavior is the problem that most commonly triggers a Check Engine light, according to CarMD.com, which sells an automotive diagnostic tool and provides repair information. The oxygen sensor unseats the formerly most common Check Engine light culprit: a loose gas cap. There are fewer reports of that problem because savvy motorists have learned to fix it themselves and consumers now buy new cars with capless gas tanks.

But don’t despair. Replacing your car oxygen sensor will keep you from wasting money by burning extra gas, and the repair isn’t horribly expensive. We know this firsthand. We had to replace the O2 sensor on our 1996 Lexus ES 300, the subject of our Debt-Free Car project, and it wasn’t as much of a hassle or expense as we had feared.

After the dreaded Check Engine light appeared in our Lexus, we plugged the CarMD device into the car’s computer to read the error code. In our case, the code was P0135, which meant that the oxygen sensor in “bank 1” was malfunctioning. It was surprising to learn that something was wrong with the car, since it still seemed to be running fine.

Even though a car seems to be behaving normally, a faulty oxygen sensor will cause the engine to start “gulping down gas,” says Kristin Brocoff, director of corporate communications for CarMD.com. She says this problem can cause up to a 40 percent reduction in fuel economy. Sure enough, when we checked our fuel record for the driving we did while the Check Engine light was on, our mpg had taken a hit.

The oxygen sensor, developed in the early 1980s, is an essential part of the car’s emissions control system, says John Nielsen, director of engineering and repair for the American Automobile Association (AAA). The sensor is about the size and shape of a spark plug and protrudes into the car engine’s exhaust stream. It determines if there is a lot or a little oxygen in the exhaust, so the engine can make adjustments to the amount of fuel being used in the engine to run at maximum efficiency.

Oxygen sensors in older cars fail for a variety of reasons, according to Bosch, a leading manufacturer of auto components. In some cases, sensors are fouled by gasoline additives or oil from worn engines. Newer oxygen sensors can last 100,000 miles if conditions are right, but often problems occur sooner.

After we plugged CarMD’s diagnostic device into the Lexus’ onboard computer port, we connected it to our desktop computer. It accessed a database of information about this engine code and how to have it repaired. Among other things, the report included an average estimate just to buy a new oxygen sensor: $168.82.

At the first sight of a Check Engine light, most owners of new cars that are still under the factory warranty would simply make a beeline for the dealership’s service bay. But car owners on a budget might want to go the do-it-yourself diagnosis route to save money. By using the CarMD device, or any engine code reader, drivers can learn what the problem is, and the skill level required to fix it, before attempting the task.

Modern cars have two to four oxygen sensors, Nielsen says. A V6 engine, such as the one in our Lexus, has one sensor in each exhaust manifold and one after the catalytic converter. The sensors simply screw into place, but reaching them can be a problem for do-it-yourselfers. Additionally, since the exhaust subjects the sensor to extreme heat, it can “seize” (become frozen in place) and be tough to unscrew. A new sensor comes with anti-seize compound to apply to the threads, but the compound should never be put on the sensor itself.

Nielsen says that while a code reader might indicate that the problem is the car oxygen sensor, there are other problems that can trigger the identical code — a disconnected vacuum hose will do it, for example.

As a first step, a car owner can look under the hood to see if there are any wires or hoses disconnected, Nielsen says. In some cases, a wire leading to the oxygen sensor could be broken or burned out. If nothing obvious is visibly awry, it’s time to go to what Nielsen calls “a trusted mechanic.” Reputable garages use an expensive diagnostic machine called a scan tool — not to be confused with an inexpensive code reader — that can watch the operation of the engine in real time and see if the oxygen sensor is actually the problem.

“Most motorists would be well served to find a shop that they trust and take their car there for all oil changes and tire rotations,” Nielsen suggests. “Then, when they have a problem with something like an oxygen sensor, they trust what the mechanic is saying rather than thinking that they’re trying to rip you off.”

In our case, we learned that the faulty O2 sensor was in the rear of the engine and difficult to reach, so the fix seemed above our skill level. Instead, we took the Lexus to Overseas Garage, in Long Beach, California. There, the mechanic told us that the new sensor would cost $117, plus $144 in labor for a total of $261. This was close to the $246 average cost cited by CarMD’s Brocoff.

While many people opt to simply ignore “Check Engine” lights, Brocoff says this can cause bigger, more costly problems later. “So the problem you could have fixed for a few hundred dollars turns into a repair of the catalytic converter, which would be over a thousand.”

Driving back from the garage, it was a relief not to stare at the glowing check engine light. This made us realize that fixing such a problem provides another benefit: peace of mind.

Simple Ways To Choosing the Right Auto Body Shop

It’s not uncommon for estimates from different body shops to vary wildly. One shop might give you an estimate for $500 while another wants $2,000 for the work. What’s the difference? And when is it OK to choose the cheaper shop?

John Mallette, owner of Burke Auto Body & Paint, in Long Beach, California, knows better than most people how to choose a reliable shop. Mallette started working on cars when he was 12 years old and has been in the body shop business for 24 years. Here are some of his tips for choosing the right shop to work on your car — particularly when you’re the one paying the bills.

1) Pay Attention to Word-of-Mouth
Any business can advertise, but you’ll do better with a shop that friends, family or acquaintances recommend. It’s a business that has proven it can satisfy customers. And it might not be the biggest or best-known shop in your area.

Mallette went to a shop years ago on such recommendations and found that the owner was a “real stand-up guy…. He doesn’t advertise on the Internet; it’s a family-owned shop,” Mallette says. “But, golly, if you take your car there, you’ll get a fair price.”

In some cases, you might get a recommendation for a small shop where the owner works on the cars himself. “That’s how I like doing business,” Mallette says. “To me it seems so much more personal and then you can understand what’s really going on with your car.”

2) Consider the Operation’s Location and Overhead
“Where you get screwed in our business is labor hours,” Mallette explains. His shop charges $40 per hour for labor. But in ritzy parts of West Los Angeles, the per-hour labor charge is $60-$65. In wealthy Newport Beach, California, Mallette has heard of $90-per-hour labor charges.

Large body shops with a lot of front-office workers probably have to charge higher rates to pay their staff. While service delivered by front-desk folks, managers and foremen gives some people a feeling of confidence in the business, it can result in estimates that are padded with non-essential work. When they’re charging more labor hours at a higher rate, your bill can add up quickly.

In his shop, Mallette says he does things by the book — literally. Body shops and garages use reference guides that estimate the number of hours required to perform common repairs.

“Let’s say somebody has damage to their fender, bumper and headlight,” Mallette tells us. “I go to my book, I write an estimate and I basically go by the hours mandated by the book.”

By contrast, the higher-end shops might decide to charge for everything in “the gray area,” meaning those things that they might have to do to fix the problem. In Mallette’s example, high-end estimates might include a charge for time spent removing the hood and the door, while his judgment call is not to perform this additional work.

3) Get Several Estimates
Taking your car to several auto body shops for repair quotes is the best way to avoid overcharges, Mallette notes. “I’ll tell people to go get some estimates and bring ’em back to me. I’ll match estimates if I can.”

And while it’s important to protect against being overcharged, you shouldn’t simply take the lowest quote. “You might get some kind of midnight guy who will say he can do it really cheap,” he says. “Stay away from those guys, because there is something they’re not doing. You could have major problems down the road.”

4) Ask the Right Questions
When choosing a body shop, “you don’t go in with your pocketbook open,” Mallette explains. “You go in smart,” and ask some key questions. Does the shop provide a written warranty? And if so, for how long? What does the warranty cover?

A one-year warranty is a minimum, Mallette says. His shop offers a two-year warranty for body work and a three-year warranty for complete paint jobs. Some shops offer lifetime warranties as a selling point, but that isn’t realistic, he says.

“Most of the stipulations and conditions those warranties require are more restrictive than the majority of people can adhere to,” he says. “So basically, the warranty becomes useless.”

Another key question is whether the shop carries fire and theft insurance. You want to be sure you’re covered if your car is destroyed, stolen or burglarized. Don’t forget to ask how long the shop has been in business. Make sure it has a business license.

You will also want to know about the materials the shop intends to use. Are new, used or aftermarket body parts going to be used? New parts are obviously the best and used parts are fine, though they don’t offer the savings people imagine. Depending on the damage to your vehicle, aftermarket parts can save a lot of money and can be just as good as the ones that come from the original manufacturer. If paint work is involved, ask how many coats of paint and clear coat the shop intends to use.

5) Follow Your Intuition
Finally, it’s important to trust your intuition about the shop you’re considering. If a shop isn’t busy, maybe that’s because customers are avoiding it because of shoddy repairs. If the place is really dirty, cluttered or disorganized, this might reflect the kind of work you could expect the shop to do with your car. Is the shop owner or manager a grouch who seems to resent answering your questions? You’ll be happier with a shop where the owner communicates well and is straightforward with customers.

“Trust your gut,” Mallette says. “If your gut tells you the guy’s shady I wouldn’t even go there.”