Here's a secret that mechanics don't want you to know: You really don't need to have your oil changed every 3,000 miles.
It's a waste of a precious resource -- not to mention money -- to take your car in every 3,000 miles or three months, experts say. Most cars don't need an oil change for 7,500 miles.
"The oil change itself is a loss leader," said Austin Davis, whose family has been in the car-maintenance business in Houston since 1937.What Your Car Mechanic Doesn't Want You to Know" and has a website called MyHonestMechanic.com.
"Most repair shops will lose money or at best break even on a $25 to $28 oil change," he said. "The whole idea is to get you to also buy an air filter, rotate your tires or buy something else while you're there."
Complaints about auto repairs consistently rank among the top 10 grievances filed to state attorneys general, according to the National Association of Attorneys General. In 2008, the latest figures available, auto repair complaints ranked No. 6 on the list.
"The easiest way to make up for money that you're losing or to increase profits is to turn up the upsell button on all your services," said Philip Reed, the senior consumer-advice editor for Edmunds.com. "Mechanics want you to get brake jobs earlier than you need them or change oil filters more frequently."
Sometimes, however, we are our worst enemies when it comes to explaining what is wrong with the car and giving away too much information. "Never reveal your budget," said Davis. "If there's steam pouring out of the hood of your Mercedes, don't tell the guy 'I hope this isn't going to cost me $2,000.'
"He'll be thinking, 'How about $1,995,'" he said.
There are no hard-and-fast rules about maintaining cars because they're all different. But experts do agree on this: You should use your car manual as your guide. It will tell you at what mileage mark the oil should be changed or the transmission fluids flushed and what intervals that maintenance should follow as well as a host of other upkeep tips.
"If there's a conflict between what the owner's manual recommends and what the dealer recommends, follow the owner's manual," said Reed. "The manufacturer made the car; they should know what it takes to maintain it and keep it running."
Pay attention to the warranty packages. Cars known for dependability will guarantee parts for as many as 70,000 miles. That's almost the equivalent of driving around the earth three times.
"Cars today are just so well made that the failure rates of parts is close to nil," Davis said.
But long before you need to turn the keys over to a mechanic, find one who is trustworthy and with whom you can build a long-lasting relationship.
"If you develop a relationship with your mechanic, you're much less likely to be ripped off," said Brandy Schaffels, the content manager for the TrueCar website. "They'll go out of their way to help you." She had a mechanic who built an air-conditioner compressor by hand at a substantial savings over buying a new one.
"If your instinct tells you that what they're telling you doesn't sound right, double-check it with another mechanic," she said.
Go in prepared. Edmunds.com has a plethora of educational and how-to categories on its site. Davis compiled a maintenance schedule for a variety of cars. See the list here.
Schaffels also recommended purchasing a device that can plug into the car's port and diagnose why the check-engine or brake light is on; that part is available at do-it-yourself car-parts stores.
"Be wary of inspections," Davis said. A 40,000-mile inspection package at $400, for example, will call for a check on everything from the oil and brake pads to the door hinges.
"You pay them $400 to tear your car apart and look for additional repairs to sell you," Davis said. "That's a great business model right there."
You don't need to replace or flush transmission fluids until 25,000 to 30,000 miles. Some cars won't need the transmission fluids touched for 50,000 to 60,000 miles and some manufacturers are moving toward using fluid that never needs to be replaced.
Look at the brake pads yourself before committing to new pads and think about changing them yourself. "It's a really well-kept secret that changing a brake pad is pretty easy," Reed said. "People get freaked out with brakes thinking that if they don't do it correctly, the car won't stop. If there's a problem with your brakes, you'll know right away."
Don't fret either if the mechanic says the brakes are about 50% worn down. They don't need to be replaced until they're 85% to 90% worn.
More from MSN Money and MarketWatch
- 10 cars that refuse to die
- Ford's Alan Mulally: MarketWatch CEO of the Year
- 5 ways to make your car last
- Auto review: 2011 Hyundai Elantra
- What to do when your car hits 100K
- 2011 Chevrolet Volt: Gas-electric marriage