Auto Pilot

By: Perry King Source: AARP.org Date Posted: 2005-03-29

Don’t know a pressure gauge from a piston ring? Here’s how to road-test a used car (without getting your hands dirty):

1. Interior

Start here, since a quick look around can tell you how well the previous owner took care of this car. Rule of thumb: if what you can see looks bad, the stuff you can't see (like the inside of the engine) probably looks even worse. First, notice how worn-out the driver's seat is, including the armrest. Obviously, rips and tears, burn marks, stains, and other evidence of misuse are indications of a hard life. Also pay attention to the driver's side door: in particular, make sure it closes smoothly and with a solid sound. Look at the rubber covers on all of the pedals. Almost always ignored by car restorers (folks who try to make old cars look new), they will tell you how much hard use a car has had.

2. Electrical System

Before you even start the car, you can check the charging system (part of the electrical system, including the battery). Turn on the headlights and leave them on for a couple of minutes, if possible pointed toward a dark wall. Then start the car. The battery should turn the engine quickly, even though you left the lights on, and when the engine catches, the lights should brighten noticeably.

3. Engine

When you start the car, the engine should fire up almost immediately and the oil light should instantly go out. Any warning lights on the dashboard should also go out. If there is an oil-pressure gauge, the needle should pop up to the middle or higher. Any car may make odd sounds when it's cold, but there should be no loud clacking, whirring, or grinding noises once the engine is fully warmed up. It should idle comfortably, without shaking the car and without noticeable changes in engine speed.

When the engine is warm and you're doing a test drive, coast down a long hill for 10 or 15 seconds with your foot off the gas. Then, when you give it gas, check the rearview mirror: a whiff of smoke is acceptable. A cloud signals engine trouble (a possible rebuild), and you should forget this car. After you've been driving a while, pull to the side and let the car idle for a couple of minutes. Then rev the engine two or three times. If you see smoke come out the back, the valve guides are worn (other expensive parts you do not want to fix).

4. Brakes

While the car is sitting still and the engine is running, push on the brake pedal. It should sink just a bit to engage the brakes, but then the resistance should be firm, not soft or mushy. When you're driving, find an open road without much of a crown (a drop-off to either side). When the road is empty and it's safe, drive about 30 miles an hour, positioning the car in the middle of the road—so that you straddle the top of the crown. Now brake gently, while loosening your grip on the wheel. The car should slow smoothly, without any shaking and without pulling to either side. If it doesn't, you've got brake problems, and you should probably pass.

5. Steering

With the car parked and the engine running, the steering wheel should have no free play (the ability to turn the steering wheel an inch or so with no corresponding movement of the car's wheels). Free play is not necessarily a reason to pass on the car, but the problem will need fixing. Another thing to notice: while the car is sitting still, with the wheels pointed straight ahead, the steering wheel should be centered, not turned slightly to one side or the other. If it isn't, the car has had some serious steering or alignment problems that were not corrected properly.

Another alignment test: just after you've rounded a corner, lighten your grip on the steering wheel. The car should straighten out by itself, without assistance. If it doesn't, there is an alignment or steering-rack problem, so it might be best to forget this car. Caution: remember to keep an even throttle as you conduct this test. And just to be safe, do it when no other cars are around, since you may have to grab the wheel quickly.

6. Automatic Transmission

With the warmed-up car sitting still, put the transmission in drive. Now, with your foot hard on the brake, give it some gas. You should feel the car trying to move right away, and then it should seem about to stall. If it does not, that's a bad sign. Next, keeping your foot on the brake (but giving it no gas), shift from drive to reverse, reverse to drive, and park to reverse. Big clunking sounds are bad.

7. Clutch

A common problem you could face when buying a stick-shift car is the clutch. To test it, while driving, rev the engine pretty high in second and shift quickly to third, popping out the clutch and giving it lots of gas as soon as you are in third. If the engine seems to be speeding up more than the car is and then the engine sound comes down to match what the car is doing, the clutch is slipping. Clutches are expensive to replace, and this car may need a new one soon.

8. Drive Shafts and Axles

As you're driving, accelerate and decelerate a few times. Big clunking sounds of any kind are bad here, too. They probably come from one of the axles, and mean it is badly worn or out of oil (which indicates it will expire completely soon). The problem could also be worn U-joints (connections to the ends of the drive shaft). Either way, forget this car.

From Outside the Auto
If you want to go the extra mile and poke around more closely, here are some added signs of trouble that you don't have to be a car expert to spot.

9. Anticipate Future Shock

Notice, from a distance of 15 feet, if the car sags in the rear—a trait common to tired rear springs. Push down hard on the car at both ends. As you release the pressure, the car should rise back quickly and stop, not pogo up and down. If it bounces, the shock absorbers are finished. Ask for $300 off the price.

10. Don't Trust Rust

Any sign of rust is a warning of trouble to come. Once started, rust is almost unstoppable, and it will eat away at the body from the inside out. Check under the carpet or mat in the trunk or rearmost area of the car in particular. This area is the most susceptible to leaks, and corrosion or rust there means you should skip this car, no matter how pretty it is on the outside.

11. Beware of Repairs

Take a magnet and hold it against the body of the car in various places. If the car has been cheaply repaired, the body shop will have used a nonmetal filler. The magnet will not stick, or will stick lightly. If there is metal right beneath the paint, the magnet will stick well. Also, check out the fit of the doors and the trunk. Gaps that are different front to back or side to side indicate that a vehicle has been hit and poorly repaired.

12. Question a Too-Clean Machine

A sparkling engine compartment in an older car is often a sign that someone is trying to spruce up a bad deal. For example, if the painted surfaces feel greasy, it might be an overenthusiastic application of good old Armor All. That can signal an owner trying to hustle you by covering up neglect.

13. Look for Leaks

The best way to check for oil leaks is to park the car, after it's been driven, on a clean bit of concrete. Anything more than a drop on the ground means there's a problem waiting. In particular, look under the back of the engine. A leaking rear main seal is expensive and difficult to fix.

14. Check Under the Hood for What's Not Good

The first thing to look for is corrosion around the battery terminals. Also notice any oil sheen or drips on the motor, which could mean an old, tired engine. The power-steering pump, always run by a belt and nearly always found near the front of the engine bay, will have oil mist near its pulley if it's getting similarly old and tired. Notice whether any wires look feathered or whitish, or torn and repaired. Pull the engine dipstick. Black oil means the car has been neglected. Pull the transmission dipstick. Transmission fluid that is not rosy-pink or that smells burnt means trouble.

15. Avoid Tired Tires

Look at the outside edge of the front tires. If they are roughed up and have a feathered edge when you feel them, then someone has been cornering the car hard or there is an alignment problem. The old test for judging if tires have sufficient tread left is to put a penny in the tread, with Lincoln's head toward the axle. If you can see the top of Lincoln's head, the tires are worn out.

Perry King is an actor and racecar driver who over the past 30 years has bought nearly 50 used cars for himself, his friends, and his family.

Additional Related Links

How and Why It Pays to Buy Used

10 Tips to Get the Best Deal on Your New Car (July and August 2004)

Listen to: Buying a New Car (AARP.org)

Listen to: Car Luxuries and Improvements (AARP.org)

Listen to: Smart Cars Are Coming (AARP.org)

Member Auto Services and Discounts (AARP.org)

Avoid Car Repair Rip-Offs (AARP Bulletin)