Another hurricane brings another reminder about buying used cars.

That’s because recent disasters like Hurricane Sandy tend to leave thousands of vehicles damaged or destroyed by floods. And even though most states have strict laws to protect us from buying them, many flood-damaged vehicles still wind up on used cars lots! In fact, a study found that half of the vehicles damaged by Hurricane Floyd, in 1999, were later put back on the road, and some of those cars are still showing up for sale to this day!

Why’s that a problem? Carl Sullivan is a professional auto inspector who says any time a car’s submerged in water, it’ll never be the same, because flood water can corrode engine parts, destroy sensitive electronics, and cause safety systems to fail, including brake pads and airbags! And because some damage may not show up for months, most dealers will declare cars a “total loss” if flood water gets any higher than the floor.

That’s why Sullivan recommends hiring someone to inspect used cars for water damage, before you buy. He says some common red flags include:

  • Condensation in the headlights or tail-lights.

  • Mud in places you wouldn’t expect to find it, like the seat belt tracks.

  • Water or mold in the spare-tire well.

  • And any kind of musty odor in the car, which could come from mold hidden under carpeting.

Of course, experts also recommend checking vehicle-damage reports, but you may not be able to trust them. That’s because some shady dealers can trick the reports, by switching the Vehicle Identification Numbers on flooded cars.

It’s something to keep in mind if you’re shopping for a used car today, because statistics show that hurricanes typically bring a “boom” in auto sales, up to 60 days after striking.