How to Inspect a Car for Rust

Even cars that look nice can have severe, hidden rust. Cheap paint jobs often hide dangerous corrosion problems that can render a car dangerous to drive. Meanwhile, repairing rust damage is difficult to do well, and professional repair is very expensive. Before buying a used car you should inspect it thoroughly for corrosion damage. It helps to be mechanically inclined, but anyone with eyeballs and common sense can effectively inspect a car for rust.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• Flashlight
• Screwdriver (any kind will do)
• Optional: Jack and Jack Stands

1. 
   Hard to see rust forming underneath trim on a nice looking fender.

   Walk around the car looking for evidence of rust. Look hard at wheel wells, around the edges of windows, and around anything, radio antennas for example, that protrudes from the bodywork. Car paint should be smooth. If you see any lumps or bubbles in the car's finish, this is evidence of rust, forming under the paint.

2. Open the hood, and get out the flashlight, even if it's daylight. Look at the engine itself. Does everything seem rusty, or does it all look like normal metal? The electrical and fuel systems can be easily ruined by corrosion, so lots of rust in the engine compartment means the car will be unreliable at best.

3. 
   Shock towers, like this one, hold the weight of the car and must be solid steel to be safe.

   Once you're done looking at the engine, look left and right at the suspension pickup points under the hood. You don't want to see more than a little bit of rust here, as these attachment points need to be solid steel in order to do their jobs safely. If in doubt, use the screwdriver to poke hard at rusty spots. If it goes through, that means the metal will probably disintegrate under the load of the car.

4. Now get in the car and turn the wheel to the right as far as possible. Get out, and go look in the wheel well with a flashlight. You should expect to see some degree of rust here, especially on a northern car. Look hard with the flashlight. Follow the suspension from the back of the wheel to the point where it attaches to the car. This area should look solid. If it isn't, it's unsafe. Reach in with the screwdriver and stab any rusty metal. If the tool punches through any metal here, the car is unsafe. Repeat this procedure for the left side.

5. Open the trunk, looking for rust all the way around the edges of the trunk opening. There should be rubber sealing gaskets all the way around the trunk. If they are missing, beware.

6. You absolutely must pull up the trunk carpeting to inspect the metal trunk floor. This carpeting is almost always very easy to pull up, and usually requires no tools. Ask for help from the seller if you feel uncomfortable doing this to someone else's car. If the seller balks or tries to change the subject, assume the trunk floor is absolutely rotten with rust, and either walk away, or subtract from your tentative buying offer.

7. Once the trunk floor is exposed, get your flashlight in there. You should probably see a spare, and the tire changing tools. If these are all rusty, you can bet that the trunk leaks. Stab the screwdriver into any part of the trunk floor that looks rusty. If the screwdriver pokes through anywhere, assume the whole trunk floor is rotten.

8. 
   Look for assemblies like this one. There should be little rust and no holes.

   Now check the rear suspension pickup points. You'll really need to yank up the carpet to find them, and they will look different depending on the car. You don't really have to know cars here, just look for any area where things look attached, and remember that you don't want to see any rust back here in the trunk area. Poke, poke, poke with the screwdriver.

9. Get in the car and poke your screwdriver into the floor in front of the driver and passenger seats. You should feel a bit of give, and you should hear a thunk as the metal screwdriver meets the (solid) metal floor. Floors are often rotten, especially in convertibles and sunroof cars.

10. If everything seems okay, you can stop here, and make decisions about the car. BUT the worst rust on a car is usually on the undercarriage, where road salt causes damage. You should at least reach under the car with the screwdriver and stab upwards, into the floors, looking for holes. However, if you really like the car, you could take it to a professional shop and have them inspect the bottom.

11. Now you must get under the car. Jack up the car high enough to crawl around underneath, and put it on at least one stand.

12. Look up at the floor of the car, and stab at anything rusty looking. Look especially at brake and fuel lines, as any rust on these could cause brake failure, fires, or lots of wasted gas. Look for cracks in under-body coating to find serious rust damage, and look to see if things look properly attached. There should be no coat hangers, wire, duct tape, or other dodgy looking repairs. Inspect the exhaust for holes, rust, and missing exhaust hangers. Look at the fuel tank for leaks, rust, and shady repairs. Take note of everything you find.

13. Bring the car down off of the jack stands. The inspection is complete. You can now decide what to do with the car, adjusting your offering price to reflect any rust damage you did or didn't find.

Tips & Warnings

• Take pictures of anything you're in doubt of. You can show these to a knowledgeable friend.
• Use some safety glasses if you get under the car. Rust particles can easily fall into your eyes.
• Always, always, ALWAYS, use jack stands when under a car. People die all the time when they decide not to.