IF YOU can't test drive a car or have your mechanic look it over, here are some tips from Clarence Ditlow, executive director of the Center for Automotive Safety, to help avoid getting hosed at an auction.

1. Decide ahead of time what car you're interested in, or possibly two or three. Then don't buy something else impulsively.

2. Estimate roughly what you want to spend, and stop there. As a guide, consult "The Blue Book" (the official used-car buying book of the National Automobile Dealers Association.

3. Look at the car in the sun, if possible. Rain and bright lights hide finish problems. Sight along the body lines, not perpendicular to them, to find dents, bulges, distortions in fenders, etc., which could signal accident damage.

4. Have someone rev the engine and watch the exhaust pipe for clouds of blue smoke which might mean the car needs a ring job. Look inside the pipe for excessive deposits.

5. Listen closely to the engine. If it knocks, pings, misses or makes strange noises, be sure you know the cause, because there definitely is a cause.

6. Check for rust, especially along the rocker panels under the doors, one of the first places for rust to start.

7. Open the trunk and look for rust inside. Also see if the paint there matches body paint. Interior surfaces usually aren't painted in accident repair work. Check the spare -- if it's unevenly worn, it may have been taken off the car to hide bad alignment.

8. Watch the car as it's being driven up to the block to see if it shifts smoothly. On automatic shifts, be sure it doesn't hesitate when the driver puts it in gear. These are transmission warnings.

9. Check the shocks by pushing up and down on the car corners. Motion should continue only about 1 1/2 bounces.

10. Notice if the brake pedal is soft and sinks too low. Be aware that brakes and steering are hard to check except on the open road.

11.Put a newspaper under the engine and a rear wheel and let the car run in neutral for at least five minutes; shift the car into the gears with the brakes on; if possible back it up. Check for any leaks on the paper, which could mean engine or differential problems.

12. Compare the wear on the brake and gas pedals with mileage on the odometer; excessive wear and low mileage should make you suspicious. Be sure to ask if the odometer is working and if the mileage is accurate; it's illegal for anyone to hide this knowledge if asked. Get the required mileage disclosure statement.