Vehicle inspection, explained

What a good inspection actually looks at

Every used car has a story. An inspection is how you read it: glass and paint on the outside, tires and the underbody below, lights, and the numbers inside. Here is a plain guide to the walk-around.

123456
  1. 1 Glass
  2. 2 Paint and panels
  3. 3 Tires and wheels
  4. 4 Underbody
  5. 5 Lights
  6. 6 VIN and interior
The checkpoints

Six places every inspection looks

A thorough walk-around is the same few questions asked of each part of the car: is it damaged, is it worn, is it original, and is it safe?

VIN chip, crack, VIN plate

Glass and the VIN

Chips, cracks and pitting in the windshield and windows. A chip near the edge can spread into a crack. On most vehicles in the US the VIN plate sits at the base of the windshield on the driver side, readable from outside.

scratch, dent, panel gap

Paint and panels

Scratches, dents and rust bubbles, but also signs of repair: a panel that is a slightly different shade, uneven gaps between doors, or overspray on trim.

depth gauge in the center groove

Tires and wheels

Tread depth, uneven wear that points to alignment trouble, cracks in the sidewall, bulges, and curb damage on the wheels.

exhaust, shaft, tank, leaks

The underbody

Fluid leaks, rust on the frame and floor pans, a bent or hanging exhaust, damaged suspension parts, and signs of an earlier impact.

lenses, bulbs, aim, plate

Lights and lenses

Cracked or fogged lenses, bulbs that are out, headlights aimed wrong, and a legible, mounted license plate.

128 450 mi ! odometer, warnings, wear

Interior and odometer

Warning lights, odometer reading against wear, seat and pedal wear, odors and water stains, and whether the VIN on the dash matches the paperwork.

Tires

Tread depth, in one picture

Tread is measured in thirty-seconds of an inch. A new passenger tire starts at roughly 10/32 in (about 8 mm). Many US states set the legal minimum at 2/32 in (1.6 mm), and tire shops often suggest replacing earlier, around 4/32 in, because wet-road grip falls off as the grooves get shallow.

The classic quick check is the penny test: put a penny head-down in the groove. If you can see the top of Lincoln's head, the tread is at or below about 2/32 in.

NewGetting lowAt the limit about 10/32 in4/32 in2/32 in tread height above the base of the groove
12345678 front of the car on the right
The walk-around

Eight stops around a car

  1. Front: bumper, grille, hood gaps, headlights, plate.
  2. Front corner: fender, wheel, tire, mirror.
  3. Side: doors, glass, sills, door gaps.
  4. Rear corner: quarter panel, wheel, tire.
  5. Rear: trunk gaps, taillights, exhaust, plate.
  6. Far side: repeat the doors, glass and panels.
  7. Roof and glass: dents, hail, chips, sunroof seals.
  8. Underneath and inside: leaks, rust, then the VIN and odometer.
Why it matters

Why dealerships inspect every vehicle

Trade-insKnow what you actually bought before you price it.
ReconditioningScope and cost the repairs before the car reaches the lot.
ListingsDescribe condition accurately, so the car on the lot matches the ad.
ServiceSpot worn tires, leaks and damage when a customer's car is already in.
Quick answers

Common questions

What is a VIN, and where is it?

The vehicle identification number is a 17-character code, in use on vehicles since 1981. It appears on the dashboard at the base of the windshield, on a sticker in the driver's door jamb, and on the title and registration.

What does "frame damage" mean?

It means the structure the car is built on has been bent or repaired after a collision. It can affect how the car drives and how it protects people in another crash, which is why inspectors look for uneven gaps, weld marks and ripples in the underbody.

Does a clean exterior mean a clean car?

No. Paint can hide repairs and a car can look fine from the driver's seat while leaking, rusting or wearing tires unevenly underneath. That is why a full inspection covers the glass, the sides, the tires and the underbody together.