How to buy a used car, save gas, change the oil, and more.

By Josh Garskof
Updated May 03, 2006
Alexandra Rowley

Road Block: You’re Want to Buy a Used Car but Have No Idea What to Look For

Best route: You need to verify the condition of the vehicle, and you need to figure out what it’s worth, says consumer advocate Remar Sutton, president of the Consumer Task Force for Automotive Issues ( “You can’t judge the car by how nice it looks or what the seller tells you.” Instead, have an independent mechanic give the car a complete inspection. In some cities, mechanics offer a service in which they go to the dealership and check out the car. But in most cases you’ll need to take the car to a mechanic. “Tell the dealer you want to leave your car with him and drive his vehicle to your mechanic,” says Sutton. “If he gives you any trouble, just walk away and buy a car from somebody else.” Expect to pay $80 to $140 for the inspection, and ask the mechanic to run a full diagnostic on the vehicle and let you know how much it will cost to make any necessary repairs and get the car in good driving order. Then you can ask the seller to make those repairs or to knock their cost off the selling price.

Speaking of price, forget about the dealer’s asking price. As with a new car, you want to negotiate up from the wholesale price, not down from the sticker price. But there’s no invoice for a used car; the best way to determine the wholesale number is by contacting your loan officer at a local bank or credit union, providing all the details about the vehicle (make, model, year, trim line, accessories, mileage), and asking for the vehicle’s “black book value.” That’s the amount the bank lends to dealers to buy that car (yes, dealers take out car loans, too), and it’s the closest thing you can get to wholesale value for the vehicle. Consumer Reports also has used-car price reports available for $12 ( “You want to negotiate a price that’s as close to the loan value as possible,” says Sutton.

Road Block: You Need to Change the Oil but Don’t Know How

Best route: Your owner’s manual will tell you the proper frequency for oil changes in your vehicle (typically every 3,000 to 10,000 miles). If you’re mechanically inclined, you can certainly do the job yourself. The manual will often tell you what kind of oil to use and how much. But in most cases it won’t offer step-by-step directions, so it’s a good idea to get a lesson from someone who knows what he’s doing. And be aware that the job is harder with some vehicles than with others, depending on the location of the oil filter. Also, you’ll need some specialty equipment, such as an oil-collection pan, driveway ramps (if you have a low-profile car), a ratchet set, and an oil-filter wrench, all of which you can buy at an auto-parts or hardware store. And you’ll have to recycle the old oil. To find a used–motor-oil collection site near you, go to If all of that seems like a big hassle, consider this instead: Hiring a pro to do your oil changes can help you find a repair shop and build rapport.

Road Block: You Burn Through Gas Rapidly

Best route: Changing the way you drive can raise your fuel economy by as much as 50 percent, says mechanical engineer Ron Graves, the director of the Fuels, Engines and Emissions Center at the Oak Ridge National Laboratory, in Knoxville, Tennessee. Here’s how to increase fuel economy.

  • Take it easy. Aggressive driving―like jackrabbit acceleration when lights turn green and hard braking at reds―burns a lot of gas. Just smoothing out your starts and stops can save you up to 30 percent in gas mileage.
  • Watch your speed. “Most passenger cars get their best fuel economy between 45 and 55 miles per hour,” Graves says. And each five miles per hour that you drive above 60 mph costs you the equivalent of about 15 cents a gallon (based on a price of $2.25 a gallon).
  • Keep the engine tuned, the air filter clean, and the tires filled to the proper pressure.
  • Reduce air conditioning use―unless you’re on the highway, where the drag of open windows sometimes consumes more power than running the A/C.
    For more fuel-savings tips, visit the U.S. Department of Energy website at

Road Block: You Break Down on the Interstate

Best route: If you can, try to pull onto the right-hand shoulder, because that’s a safer place to be than the center median. Put on your hazard lights, and then decide whether you feel comfortable getting out of the vehicle. If you’re in an area where you feel safe―and the weather isn’t subfreezing―climb out and move up the embankment and away from traffic, says Mike Scott, owner of Scotty’s Carriage Works, a towing service in Cameron, Missouri. “Some people stand in front of the car to try and shield themselves from traffic,” he says, “but that’s a bad place to be if your car gets hit.” Instead, get away from the highway. If you don’t feel comfortable exiting the vehicle, move to the passenger side (assuming that’s the side away from traffic) and fasten your safety belt.

Some highways have motorist-aid call boxes; or use your cell phone or automobile-based communication system to call your automobile club or roadside assistance service. Be sure to say you’re stuck on the highway and worried about your safety―that will get help there faster. “I might have five calls waiting for me, but if I hear about someone stuck on the highway, that becomes a priority,” says Scott. “The person whose car is sitting in his driveway is going to have to wait for a jump.” If none of those options are available to you, just hunker down and wait for a patrol to come by or for another motorist to see you and call for help.

Road Block: You See a Car Has Broken Down―Should You Stop?

Best route: Unless you’re a mechanic or an EMT, it’s not a good idea to stop at the scene of a highway breakdown or accident. Of course, you need to use your judgment: It’s certainly nice to help a pregnant woman change a flat tire or to comfort an accident victim until help arrives. “But all too often, good Samaritans wind up becoming statistics themselves,” says California Highway Patrol officer Michael Wright. Not only might you get in the way of emergency personnel when they arrive but you also run the risk of getting hit by a passing car or discovering that the person you’re trying to help is actually a criminal who’s faking car trouble to lure his prey. “Don’t risk your life trying to save another,” says Wright. Instead, he says, “be a good witness.” Drive past the scene; look for the nearest highway mile marker, overpass, or exit sign (to help police quickly pinpoint the location); pull off at the next safe spot; and call for help.

Road Block: You’re Driving…and Sleepy.

Best route: Drowsy driving is estimated to cause more than 100,000 accidents―and 1,500 deaths―in the United States each year, according to the National Highway Traffic Safety Administration, so try to limit yourself to no more than two hours of driving at a time. If you’re traveling with another adult, take turns driving. If you’re not, take plenty of breaks during long treks.

“The only real solution to drowsiness is sleep,” says Darrel Drobnich, director of the Drive Alert, Drive Alive program of the National Sleep Foundation ( “Look for a safe place to park and take a 15- to 20-minute nap―you’ll wake up refreshed.” Don’t pull over on the side of the road, however. Find a well-lit and populated rest area or convenience-store parking lot, Drobnich says: “Lock your doors, and you might even tell a person working inside that you’re going to be there so he can watch out for you.” Caffeine can also help. For most people, about 160 milligrams (the average amount found in two cups of coffee) can provide a significant boost in alertness for a couple of hours. (If you’re a frequent coffee drinker, however, you may need a much higher dose.) But the caffeine content in brewed coffee varies widely, so it’s hard to ensure you’ve gotten enough of it. Alternatively, you can get a measured amount with an energy drink, such as Red Bull, or with a caffeinated mint or gum, such as those from Penguin (, all of which list caffeine content on the package. Mints and gums also take effect quickly and are easy to keep handy in a glove compartment. Coffee and energy drinks, on the other hand, require about 30 minutes to enter your system. “So if you’re drinking your caffeine,” Drobnich says, “why not take a nap while you wait for it to kick in?”