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. On average, 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. He's the author of "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.
Because car manufacturing has become so sophisticated and less reliant on human intervention -- more computers and technology are producing and installing parts, for example -- the car-repair business isn't as robust as it was 10 and even five years ago.
"The easiest way to make up for money that you're losing or to increase profits is to turn up the up-sell button on all your services," said Philip Reed, 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 Mr. 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 rule of thumb: 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 too 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 it does come time to turn the keys over to a mechanic, find one that is trustworthy enough with which to build a long relationship.
"If you develop a relationship with your mechanic, you're much less likely to be ripped off," said Brandy Schaffels, content manager for the TrueCar.com 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 to 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.
Here's a primer that will help you from getting scammed by mechanics.
"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 will 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.
Ask for the replaced parts. Some states may require that the old parts are given to car owners with the itemized bill. But know what you're getting. Davis said he once gave an established customer an old air-conditioning compressor rather than the water pump he replaced to make the point. "We had a nice discussion about what a water pump is, what it does and what it looks like," he said.
Put chalks marks on car tires before having them rotated. Tire rotation is important because it keeps the wear and tear on the tires even and it extends the life of the tires. With all the turning, stopping and parallel parking, the front tires wear out substantially quicker than the back.
When you have them rotated, you are swapping the front tires for the back, not side-to-side or criss-crossing. But it's tough to tell if the tires have been actually changed unless you put chalks marks on them -- say, FL for front left, RR for rear right, etc.
Tire rotations are directly tied to certain mileage marks. There's a 5,000-mile minimum by some manufacturers, but 7,500 miles is the average. Some tires don't have to be rotated for as many as 20,000 miles.
Beware of the check-engine light. It's another profit center for a lot of dealerships and garages. The check-engine light is a sensor that is telling you that something is amiss in the car. It doesn't mean the car will self-destruct or die suddenly on a highway.
"Probably the most common cause of the check-engine light is that the gas cap is not on tight enough," Reed said. The sensor has responded to the extra oxygen going through the gas line and it will go off once the cap has been tightened or the entire tank has been used.
Many mechanics will offer free diagnostic tests to tell you why the check-engine light is on. Consider that another red flag.
"Mechanics can tell you anything once the check-engine light comes on," Reed said.
Ask the mechanic to show you the problems. If the transmission fluid is not pink, but a dark brown, it's time to change it. If it's gritty because of accumulated pieces of metal and plastic, changing it could cause the transmission to slip further. If the dip stick for the transmission smells like barbeque sauce, then there are problems.
"Don't be afraid to ask them to explain these things to you," Davis said.
Keep a precise record of repairs and check them before you bring the car in. Schaffels said she used to keep a log of every tank of gas she purchased, where the mileage stood, what she paid for the gas and how the fuel economy tracked.
"If your vehicle's fuel economy has changed, it tells you that something needs to be adjusted," she said. It could be as simple as putting air in the tires to replacing rotors or plugs.
Know your car. Listen to how it starts and stops, how the wheels and brakes sound when you turn corners or come to quick stops. How does the motor hum? Does it rattle anywhere? Know how your car sounds when it's running well so that you know what sounds bad when it's not
"If you know what it sounds like when it's not running well, that makes it easier for the mechanic to fix the problem," Schaffels said.
Communicate well. The worst thing you could do is throw the keys on the counter and tell the mechanic to figure out what is wrong with the car. Let him know what your problem was, what the sound was you were hearing and from where.
"Give the mechanic enough information about the problem so that he's not spending hours and your money to figure the thing out," Davis said. "You don't walk into your dentist and say, 'I'm pretty sure it's that tooth. Just go ahead and pull it.'"
Be nice. Your car breaks down on your way to work the day of the huge presentation. You're angry and desperate. It's not the mechanic's fault, so don't direct your frustration at him. It could end up costing you. Davis's father charged a 10% penalty premium for customers who were rude to him or his employees because of car breakdowns.