First pull a carfax like everyone has said and take that document with you.
When you get their do the following:
Walk around the car, ask the owner if it has ever been in any accidents. carry a magnet withyou and place it on any of the panels to see if it stays or falls off. If the car has been in an accident and there is alot of bondo then the maget will not stick.
Open up the doors and look in the inbetween the door and panels to see any paint overspary or tape lines, another way to tell if a car has been painted.
Pop the hood and put your hand on the top of the engine block to see if it is hot, warm or cold to the touch. Some people will run the car for a little bit before the buyer gets there if the car has trouble starting for the first time. If the engine is hot, ask why did they start it up. GO around back by the exhaust pipe and have another person start the car. look for any Black or Blue smoke coming from the exhaust pipe. A small amount initially isnt bad but a constant amount if the person revs the engine means their could be oil leaking between the seals.
Look at the overall condition of the car, is it washed, is the interior clean, is the engine bay oil free. This tells you alot about the owner and how they take car of the car. Also, ask for any service history records to see if they did any or have kept any, dont just believe what they verbally tell you.
Look under the hood and pull the oil cap off, shine a flasklight in there and look at the conditon of the inside. Look for any clump sludge looking substance, this means the oil hasnt been changed in a timely matter. Pull the oil dipstick and look at the color and texture of the oil to see if it has been kept up well. Ask the seller when they did the last oil change to see if they have an answer.
From inside the car:
Start the car up, listen to the idle and make sure it doesnt sputter or try to stall. Turn the steering wheel all the way left to all the way right, listen for any poping sounds. A slight hissing sound is normal (powersteering pump doing its job). Check all fo the electronics, especiall power windows/locks (roll all the way down/up each window).
Turn on headlights, if near a wall look at the beam pattern (an off beam pattern could be indicative of a previous accident).
Driving the car, press the brakes firmly when coming to a stop, listen for any grinding noises. A little sqeeking is okay, just dust between the pads and rotors. Listen when you make right or left turns for any noise from the fron wheel areas:
- popping noise = CV joint issue
- Grinding noise = Bearing issue
- Rattle noise = Shock/Spring seating issue
If you do find anything worng with the car that wasnt told to you and you still want to buy it, you can use those issues to get a lower price. The carfax document is good but is never 100% especially if the seller paid for the damage out of pocket and not through insurance. Make sure to look at the Odometer (mileage) reading on the carfax and verify what the miles are on the actual car to make sure their is no discreapcies between the two. I had viewed a 2003 auto with a clean carfax report (no accidents) but found paintng edge tape inbetween the door and panel. I also found a paint line after removing the piece of tape. So always do a visual check and dont just take carfax word for it. Carfax only has what is reported to it, if the owner paid for the work out of pocket and never filed a claim, carfax will never know. Good Luck...