A pre-purchase inspection is a good idea before buying any used car. However, at $200 to $300 per vehicle, it’s not a service you should hire right away. In addition to running a vehicle history report, reviewing service records, and taking a thorough test drive, you can use these DIY used car inspection tips to spot potential problems yourself. These steps can help you eliminate obvious problem cars, but they won’t uncover every hidden defect.
DIY Used Car Inspection Tips: Before You Start
Bring a flashlight, a tire pressure gauge, paper towels, and your phone for photos and notes. An inexpensive OBD2 scanner is helpful, too.
- Inspect in daylight. Park on level ground with enough space to walk around the vehicle.
- Request a cold engine. Ask the seller to leave the car unstarted before your visit. Some starting problems and noises are easier to notice when the engine is cold.
- Review maintenance records. Look for documented oil changes and other scheduled services.
- Work safely. Keep hands away from moving parts. Never crawl underneath a car supported only by a jack. Start the car only in a well-ventilated area.
Check Out: 5 Must-Have Tools for DIY Car Inspections
1. Body, Glass, and Undercarriage
Start outside before opening the hood. Walk around slowly and compare both sides.
- Compare paint and panel gaps. Mismatched colors, overspray, and uneven gaps can suggest previous repairs. These clues don’t automatically mean the car is unsafe or a problem, but they deserve questions.
- Look for rust. Inspect wheel arches, lower door edges, rocker panels, and visible areas underneath. Flaking metal or holes require professional attention.
- Check glass and lights. Look for windshield cracks, damaged mirrors, broken lenses, and moisture inside light housings.
- Open everything. Doors, the hood, and the trunk or liftgate should operate without binding.
- Look underneath from the perimeter. Use your flashlight to spot hanging components, wet areas, or obvious damage.
2. Engine and Exhaust
Check the engine compartment with the engine off and cool, then observe startup from a safe position.
- Look for leaks. Investigate wet, oily areas around the engine or beneath the car. A freshly cleaned engine can make leaks harder to spot.
- Inspect visible belts and hoses. Look for fraying, cracks, swelling, or obvious deterioration.
- Listen during startup. Note prolonged cranking, persistent knocking, squealing, or rattling. Record unfamiliar sounds for the mechanic.
- Watch the exhaust. Brief condensation on a cold day can be normal. Persistent smoke after warm-up needs checking out.
- Observe the idle. Notice shaking, repeated stumbling, or stalling.
Don’t reach into the engine compartment while the engine is running.
3. Fluids and Cooling System
Use the owner’s manual to identify reservoirs and follow the correct checking procedures.
- Check engine oil. If the car has a dipstick, follow the manufacturer’s instructions for checking the level. Investigate an unusually low reading.
- Inspect the coolant reservoir. Check the indicated level only when the engine is fully cool. Never remove a hot cooling-system cap.
- Check brake fluid. Check the reservoir level. Low fluid needs investigation; adding more doesn’t explain the cause.
- Look for puddles. Clear water after air-conditioner use can be normal condensation. Other fluids need identification.
- Watch engine temperature. During the drive, note overheating warnings or an unusually high gauge reading.
4. Transmission and Drivetrain
A DIY inspection should include observing how the vehicle drives.
- Select forward and reverse. With your foot firmly on the brake, note delayed engagement, harsh banging, or difficulty selecting a gear.
- Check acceleration. The car should gain speed without repeated shuddering or unexplained surging.
- Watch for slipping. Engine speed rising without a matching increase in road speed can indicate trouble.
- Evaluate a manual transmission. Note clutch chatter, grinding, or difficulty shifting.
- Listen during turns. Clicking, clunking, or vibration deserves attention.
Don’t assume every transmission has a dipstick. Leave fluid checks to the mechanic when the procedure requires special equipment or more involved techniques.
5. Brakes
Begin with gentle braking in a safe area before entering faster traffic.
- Check pedal feel. Note a spongy pedal, excessive travel, or a pedal that slowly sinks under steady pressure.
- Listen and feel. Grinding, strong vibration, or repeated pulsation during ordinary braking warrants inspection.
- Watch the vehicle’s path. Notice whether it pulls noticeably to one side when stopping.
- Check warning lights. Investigate brake or ABS warnings before proceeding.
If stopping ability feels questionable, don’t continue the test drive.
6. Tires, Steering, and Suspension
Tires can reveal both immediate expenses and possible mechanical problems.
- Check pressure when cold. Compare readings with the driver’s door placard, rather than the maximum pressure molded into the tire.
- Inspect tread and sidewalls. Look for shallow tread, cracks, bulges, exposed cords, and uneven wear.
- Compare all four tires. Check their sizes against the vehicle’s requirements.
- Evaluate steering. Note excessive looseness, unusual effort, wandering, or vibration. Keep control of the wheel throughout.
- Listen over ordinary bumps. Clunks and excessive bouncing can suggest worn components.
7. Electrical Equipment and Interior
Small faults can add up, so test individual features.
- Check dashboard lights. Observe the startup check and note warnings that stay illuminated.
- Test lighting. Check headlights, brake lights, turn signals, hazards, and reverse lights with a helper.
- Try the controls. Operate windows, locks, mirrors, seats, the horn, wipers, and infotainment.
- Test climate control. Confirm heating, cooling, fan speeds, and defrost operation.
- Inspect safety belts. Check buckles, retraction, and visible damage.
- Check for moisture. Look beneath mats and in the trunk for dampness, staining, or musty odors.
Scheduling a Professional Used Car Inspection
After following these DIY used car inspection tips, share your observations and concerns with the mechanic. This technician should be independent of the seller and have familiarity with the vehicle you’re considering. The inspection should include a diagnostic scan, a road test, a review of the car’s maintenance status (and future needs), and an undercarriage inspection (ideally with a lift). For a hybrid or EV, choose someone qualified to evaluate its high-voltage systems.