Car Talk: The Secrets of Auto Repair Shops

Plus, tips on working with a mechanic

By: Les Jackson

I bought my first car at age 14. By the time I turned 15 and got a learner's permit, we--the car and I--had accumulated some 200 miles up and down my parents' driveway. I also had accumulated a decent box of tools and was learning how everything on the car worked.

I was, and still am, a gearhead--obsessed with automobiles. In the past 50 years, I've worked on hundreds of cars. I've restored a dozen British and American classics, built engines and transmissions, and taught automotive theory.

And I've seen the industry change. Gone, for the most part, are the days of the cluttered, dirty garage with old parts on the floor, dim lighting, and mechanics who wipe their hands with oil-soaked rags. Those mechanics have been replaced by a new breed trained in electrical theory and mechanical and computer systems. Now called "technicians," they generally work in clean, well-lit shops.

The National Institute for Automotive Service Excellence gives exams in more than 40 specialties, and good mechanics aim to be ASE-certified in a number of automotive systems. ASE master certification is considered the gold standard.

Most auto technicians are honest and hard-working. Some aren't. The world of auto repair is still susceptible to incompetence and scams. The volume of complaints to federal, state, and consumer-protection organizations suggests that unnecessary or faulty repairs cost consumers millions of dollars annually. Finding a shop you can trust--see our list of recommended garages on page 135--is the best way to avoid wasting money on a car. What follows is my advice on preventing bad experiences.

Oil Change Every 3,000 Miles?

Many people believe they should change their car's oil every 3,000 miles. In my opinion, it's one of the biggest myths in the auto-repair industry.

The last time cars needed to have such frequent oil changes was in the early 1970s, before clean fuels, computer controls, and more sophisticated engines and oil chemistry.

Don't take my word for it--trust the engineers who designed your car. They know more than anyone else who services it, and they wrote into your owner's manual the actual oil-change requirements. Most cars can safely run 7,000 miles or more before an oil change; some makes and models can go up to 15,000. Many vehicles have sensors and software that will monitor your driving conditions, such as long distances versus stop-and-go traffic, and tell you when to change your oil.

In an effort to reduce pollution from waste oil, the state of California has created a website (checkyournumber.org) that gives manufacturers' recommended oil-change intervals.

Well over 30 brands of oil additives are for sale in stores and on the Internet. They claim to give a car greater fuel economy, longer engine life, more power, lower emissions, and smoother operation. Don't waste your money. No manufacturer recommends additives, and using them can void the warranty. Carmakers have spent billions on sophisticated fuel delivery and other technologies to achieve reliability and performance.

More Services You May Not Need

There are other high-profit services most vehicles don't require during their lifetime. Here's a look at some common ones.

Engine Flush

The sell: Engines develop sludge, and a flush removes that sludge.

The fact: I've heard people in the auto-service industry call this a "profit center," an easy-to-sell but unnecessary procedure. An engine flush can actually harm engine components.

Injector Cleaning

The sell: Fuel injectors become dirty and clogged and rob the engine of power and fuel economy, so there are services to solve the "problem," from putting additives in the fuel tank to flushing the injector assembly.

The fact: Most cars never have problems with fuel injectors. Besides, the only way injectors can be cleaned properly is by removal and disassembly, which is hardly ever done. Your engine's computer will tell you if there's a fuel-delivery problem; otherwise, you can leave things alone. If the computer does indicate a problem, have the fuel filter checked. Clogged fuel filters cause most problems.

Head-Gasket Replacement

The sell: Oil or coolant leakage from the top of the engine may indicate that the head gasket is failing, so an expensive replacement is needed.

The fact: Head gaskets seldom fail; if they do, the engine will run poorly and blow smoke. All engine gaskets will begin to seep oil after a certain mileage and amount of time, so if the engine is running fine and you're not having to top off the oil frequently, there's likely nothing to worry about.

Timing-Belt Replacement

The sell: Many shops suggest replacing a timing belt before it's necessary. They may claim that the belt never lasts that long or that it has stretched and is altering the engine timing or that it's about to fail and destroy your engine.

The fact: Trust your owner's manual on when the timing belt should be replaced; most manufacturers suggest it at intervals of 60,000 miles or more. There's no way for a mechanic to see that a belt is failing without removing some components--it can run silently until it breaks. While it's true that in older cars a broken timing belt can harm the valves, vehicles made in the past decade or so are designed not to experience engine damage if a timing belt breaks.

Emission-System Repairs

The sell: Your car failed emissions inspection; the shop suggests a system overhaul.

The fact: The system may need repair, but many owners pay for oxygen sensors, catalytic converters, and other emission-system components when they shouldn't. Vehicles made since 1995 carry federally mandated warranties that cover those components for eight years or 80,000 miles. Reputable shops will tell you about this and refer you to a dealership if they can't get the manufacturer to authorize repairs on-site.

Scheduled-Maintenance Add-Ons

The sell: You've brought your car in for its scheduled maintenance--say, at 30,000 miles--and the shop recommends other services, claiming that the scheduled-maintenance checklist is only the minimum requirements.

The fact: Those scheduled-maintenance intervals are written into the manual to address known component lifetime issues and to allow technicians to monitor other components that might exhibit premature wear. A lot of shops add unnecessary services to those listed in the scheduled maintenance. When taking your vehicle in, agree only to those items listed unless there's an obvious problem.

Dealer or Independent Shop?

Surveys show that most consumers prefer to take their vehicles to independent garages for repairs. Cost and convenience are the most frequent reasons why.

That said, it's risky to have your new, in-warranty vehicle serviced at an independent shop for anything other than tires, batteries, and wiper blades. If an independent shop services a major component of your vehicle and something goes wrong, the manufacturer may not have to honor the warranty. I would suggest not taking your vehicle to an independent shop for major repairs until your car is out of warranty.

Many independents use generic or rebuilt parts that aren't made by the same company that made the original parts for your car. These are generally cheaper and sometimes justified, but major components--especially safety or drive-train equipment--should always be OEM, or original-equipment manufacturer. Rebuilt or generic components might use structurally weak materials that can fail or wear out quickly or, in the case of safety equipment, fail to operate.

When it comes to major repairs on a newer vehicle--such as engine or transmission rebuilding or a fuel-injection system--it's generally better to take the car to a dealership. It will have the most up-to-date diagnostic systems, tools, and technical training, and a larger percentage of dealership technicians are ASE-certified. Although its parts and labor rates might be higher, there's a greater likelihood that the problem will be repaired without subsequent issues.

Dealer warranties on such work are typically better because of franchise obligations that the dealers must honor. Dealers may also participate in manufacturers' unofficial "silent warranties," under which certain components with higher failure rates are repaired at no charge.

Skip the Extended Warranty

Where you bring your car for repairs may be dictated by whether you bought an extended warranty. Extended warranties promise to protect against unexpected, costly repairs.

While an extended warranty may sound good, I'd suggest not buying one until you understand the terms of the contract and who is responsible for providing repairs.

An extended warranty isn't a warranty--it's a service contract. The cost averages about $1,000 but can be more than $3,000 depending on the company and the vehicle's model, age, and mileage. Extended warranties commonly have deductibles and limited payments that are keyed to the value of the vehicle.

While some extended warranties are offered by dealers or manufacturers, others are sold through independent companies. Many outside service-policy companies have gone out of business, leaving behind angry customers.

"An extended warranty is only worth considering if the vehicle you're buying has a below-average reliability rating," says David Champion, director of auto testing at Consumer Reports. "Otherwise, it's not cost-effective. But if you do buy one, make sure it's backed by the manufacturer. Better yet, open a savings account and deposit the money you would have spent on a contract every month. It will accumulate to pay for future repairs or a down payment on a new car."

How to Find a Good Shop

If you're looking for a good repair shop, ask friends and neighbors for referrals. You'll also find a list of reader-recommended garages beginning on the next page.

When you visit a shop for the first time, look around. Clutter, spilled fluids, disorganization, dirty restrooms, and shabby equipment generally indicate a poorly managed business. It's a good sign if a shop's labor rates are clearly posted.

Bear in mind that a shop can have the familiar blue ASE sign in the window, but all that means is that at least one technician has passed exams. Ask how many technicians are certified and in which areas. Separate certifications are offered for electrical systems, engines, transmissions, drive trains, bodywork, suspension systems, and more.

If possible, talk with the technician who would be doing the work on your vehicle to assure yourself that he or she is experienced enough to solve your problem.

When you bring in your car for repair, the shop should present paperwork that spells out the limit of the shop's liability, the parts/labor warranty, and what remedies you'd have if something went wrong. That document is a contract, so it makes sense to take your time and read it.