Unless you're a car mechanic yourself, dealing with a repair shop may require a leap of faith. But if you pay attention to what your mechanic says (and does), you'll find clues that could tell you whether you're being bamboozled. Here are some things mechanics may say when they're planning to take you for a ride—and we don't mean in your car.

1. "Get that engine flushed right away or it's toast."
   Beware if your mechanic's idea of "scheduled maintenance" bears little resemblance to the recommendations in your owner's manual. Some shops "build the ticket" (translation: pad the bill) by recommending extra and often unnecessary procedures, such as engine and transmission flushes, or by scheduling some tasks prematurely. Some hawk high-priced "generic" maintenance schedules that may omit procedures your car needs.

Be especially concerned if the shop makes every recommendation sound like an emergency, says Larry Hecker, president of the Motorist Assurance Program (www.motorist.org), a nonprofit group that accredits repair shops.

2. "That rebuilt Camry alternator will run you $899."
   If you happen to know that your cousin paid only $399 for similar work, you'd better call around to check. Although good shops may charge higher prices to cover the cost of top-flight technicians and equipment, bills that are always 20 to 30 percent more than the going rate should put you on guard, warns John Nielsen, director of AAA's Automotive Repair Network. You can poll other shops to find out how much mechanics in your area are charging for common repairs and maintenance. For complex problems, try comparing the price of the parts alone by calling parts stores or dealer parts departments, advises Deanna Sclar, an auto repair expert and author of Auto Repair for Dummies.
3. "We thought the new fuel injectors would fix it, but it looks like you need a new fuel pump."
   Uh-oh. You may be dealing with a so-called parts replacer, that is, a mechanic who's literally rebuilding your car because he can't diagnose the problem, says Chuck Roberts, executive director for industry relations at the National Institute for Automotive Service Excellence, an organization that certifies auto technicians. Make the mechanic justify the initial repair. Even if it was an honest misdiagnosis, the shop should refund the amount of the first repair or discount the next one. If the mechanic gets the diagnosis wrong again, stop replacing parts and replace the shop.
4. "With some cars, it's not unusual to go through a starter every year."
   Yeah, right. This may be a tip-off that the shop did the work incorrectly or used poor-quality or makeshift parts instead of proper ones. Call some other shops to find out what they think or check the Web to see if there's a discussion group devoted to your model and its problems. You might also want to take the car to another repair shop for a second opinion. If the original job was lacking, ask the shop that did the work to repeat the repair either without charge or at a substantial discount.
5. "You have to bring your car back to the dealership for service."
   Sure, the dealer wants all the lucrative repair and maintenance jobs. But generally, you need to use a dealer only for work covered under the warranty, recalls, post-warranty fixes you're hoping the manufacturer will pay for under its "good will" program, or high-tech systems that require a dealership's specialists.

How to talk to your mechanic

Getting the right repairs at a fair price depends partly on communicating with your mechanic. Here's what to say and to expect:

• Describe the problem fully. Provide as much information as possible. Write down the symptoms and when they occur. If possible, talk directly to the mechanic who will be working on your car.
• Don't offer a diagnosis. Avoid saying what you think is causing the problem. You may be on the hook for any repairs the shop makes at your suggestion, even if they don't solve the problem.
• Request a test drive. If the problem occurs only when the car is moving, ask the mechanic to accompany you on a test drive.
• Ask for evidence. If you're not comfortable with the diagnosis, ask the shop to show you. Worn brake pads or rusted exhaust pipes are easy to see. Don't let the mechanic refuse your request by saying that his insurance company doesn't allow customers into the work area. Insist on evidence anyway.