How to Inspect a Used Car Like a Pro (And Avoid Costly Repairs)

That car might look perfect, but what’s hiding under the hood? Here’s how to make sure you’re not getting ripped off.

You’ve found the one. It’s the right price, the right color, and the mileage is reasonable. The listing says it's in "excellent condition," and the seller swears that it “runs great.” But before you shake hands and part ways with a new vehicle, let’s pump the brakes for a second.

Buying a used car is part excitement, part impulse, and part high-stakes gamble, and a pre-purchase inspection is the best insurance policy against winding up with a money pit of a car. You don’t want to discover after it’s too late that you’ve acquired a lemon, stuck in a rock in a hard place.

So before you commit, here’s how to inspect a used car like a pro (without actually needing a pro), what red flags to watch out for, and, for your best interest, why taking it to a qualified mechanic is still a legitimate  move you can make.

First Impressions Matter, What’s the Car Telling You?

Before you even touch the hood, take a step back and observe the whole picture. A car’s exterior can tell you a lot about its past. Look for uneven body panels, doors that don’t quite line up, or mismatched paint. Often left unnoticed, these are classic signs of previous accidents or shoddy repairs.

Now, take a slow lap around it. Are the tires wearing evenly? If not, that could mean alignment problems or suspension issues. Check the stance of the car too, does it sit level, or does one side sag lower than the other? A leaning car could mean a busted suspension that’ll drain your wallet faster than a gas-guzzling old chevy.

And then, there’s the rust. The slow and silent car killer. Surface rust on minor spots? Fine. But if the frame or undercarriage is corroded, you might be looking at a serious safety hazard. Rust doesn’t ever stop, it spreads.

Under the Hood, Where the Truth Resides

Alright, time to pop the hood. No, you don’t need to be a ASE certified mechanic, but a quick glance can reveal a lot.

Pull the dipstick. Clean oil should be a golden brown. If it’s pitch black and sludge-like, the owner has probably been neglecting oil changes. Worse, if the oil looks like a frothy milkshake, you could be dealing with coolant mixing with the oil, a sure sign of a blown head gasket. If you see this pack up and leave the scene that’s one headache you don’t want to deal with.

Next, check the rest of the fluids such as the coolant, brake fluid, transmission fluid. Low or dirty levels scream neglect. Touch and feel the belts and hoses, if they’re dry, cracked, or frayed, they’re due for replacement. Look at the battery if you see crusty, corroded battery terminals it might not last through a cold winter.

And finally, start her up and sniff the air. A burnt oil smell? Could mean leaks. A sweet smell? That’s likely coolant, another bad sign. If anything looks or smells off, it’s off. You can generally trust your gut here because were talking a about a serious investment.

Looking Inside the Car

A car can look flawless on the outside but be a disaster inside. Sit in the driver’s seat. Does it smell musty? Could be mold or even flood damage.

Turn everything on. Power windows, locks, mirrors, A/C, heat, radio, windshield wipers, test it all and leave no stone unturned. Dashboard warning lights? If that check engine light is glowing, you’ll want to scan for trouble codes before making any decisions.

Press the brake pedal. If it feels spongy or sinks to the floor, you could be dealing with a brake system issue, and that’s not something you want to gamble on, brakes and brake repair can be pretty pricy.

A well-kept interior usually means the owner actually cared about the car. A trashed interior? That’s a red flag that the previous owner probably didn’t take care of anything under the hood either.

Test Driving, How It Actually Feels on the Road

Now for the moment of truth. A car can look pristine in pictures, but the way it drives tells the real story.

Start it up. Listen for weird engine noises: ticking, knocking, or anything that sounds like metal grinding against metal.

When you hit the gas, does it respond smoothly? A car that hesitates, jerks, or struggles to accelerate might have engine or transmission problems lurking beneath the surface ready to show up within a short period of time.

Braking should feel firm and predictable after you’ve driven for a minute or two, not spongy or noisy. If the car pulls to one side when you brake, you might be looking at worn brake pads or suspension issues.

Steering should be comfortably responsive and straight. If the car drifts without input, alignment might be off, or worse, there could be suspension or frame damage.

While driving down the road, listen for odd noises such as clunks, rattles, or squeals. If something doesn’t sound right, again it probably isn’t right.

Where Most People (& Even Some Pros) Never Look

Most people never check underneath the car because they either don’t know to or are too lazy, but that’s where some of the worst problems hide.

Get low, on your back if needed, and look for leaks. A few drops of water from the A/C? Normal. A puddle of oil, coolant, or transmission fluid? Huge problem.

Check the exhaust system. If it’s covered in rust or rattles when you tap it, you’re looking at an expensive repair waiting to happen.

Finally, inspect the frame. If it looks bent or repaired, walk away. A damaged frame can ruin how the car drives and compromise safety outright.

Why a Mechanic Should Do the Final Inspection

You can do all of these checks and still miss something. Mechanics have tools and experience that let them dig deeper. They can scan the car’s computer for hidden problems, check the suspension and undercarriage, and tell you if that deal is actually a disaster in disguise.

Plus, if any of the above content was confusing to you, it’s in your best interest to hire a mechanic because gambling on a rather large investment isn’t smart. A pre-purchase inspection at a trusted auto repair shop could be the difference between a smart buy and a expensive mistake.

Be Smart, Save Money, Drive Happy

A pre-purchase inspection isn’t about being overly cautious, it’s about being smart. No one wants to spend thousands on a car, only to find out later that it needs thousands more in repairs.

If you’re 100% confident in your ability to check everything, go for it. But if you want total peace of mind, let a trusted car repair shop take a final look.

Take your time, ask the right questions, and never be afraid to walk away from a bad deal. The right car is out there and you just need to make sure it’s not hiding something under the hood.

Happy hunting.