Shopping for a used car is a little trickier than shopping for a new one. If you aren’t careful, you could end up with a car with enough problems to make you a regular at your local mechanic.

Want to avoid that? Here are a few warning signs that should set off some red flags when you’re shopping.

- The first warning sign? A shady seller. For private parties, always ask why they’re selling the car; if they can’t give you a good reason, they might just be unloading their troubles. Finally, if they won’t let your mechanic inspect it before buying, it’s time to move on.

- When you see the car, watch out for these warning signs:
• Rust, which can be expensive to repair and nearly impossible to reverse. It isn’t just on the visible parts of the car, either. Bring a flashlight and look for rust on the underside, in the wheel wells and on the muffler and exhaust system.
• Check the tires. See how much tread is left, and if there’s even wear between the left and right tires. If the wear is uneven, that can mean alignment problems. And if the tires are bald, that’s downright dangerous.
• Check the fluid levels. If a car is low on oil, it could mean the owner neglected a lot of other maintenance, too.

- Finally, take a test drive. That alone can reveal even more signs. If the car doesn’t track straight when you take your hands off the wheel, or if the brake pedal pulsates or the engine makes odd noises, it’s possible or even likely that the car hasn’t been very well-maintained.