
Methods for inspecting the quality of a used car: 1. Check the exterior wear and tear. Choose a well-lit area and observe the car at a 45-degree angle to spot any scratches or hidden dents; 2. Inspect the body frame for damage. If the car has been in a major accident, the frame will show varying degrees of dents or misalignment; 3. Find out why repainting or bodywork was done—whether it was due to minor scratches or a severe collision; 4. Check the wiring harness in the engine compartment for corrosion or aging, and inspect the engine block and mechanical parts for mold spots; 5. Look for leaks in fluids such as engine oil, brake fluid, and coolant.

I'm the kind of person who can spend half a day at a used car market. When checking a used car, don't just look at whether the paint is shiny. Uneven paint thickness or color differences usually mean it's been repainted. Run your hands along the edges to feel for any rough texture. Lift the trunk mat to check for rust in the spare tire well—factory welding points there should be neat and uniform. The most honest inspection comes from getting down to look at the undercarriage; any scrapes, rust, or oil leaks are immediately obvious. Start the engine and listen for smooth operation—blue smoke on a cold start definitely means oil burning. Test all four doors for unusual noises and fully extend the seatbelts to check for water stains. Always test-drive on bumpy roads; a loose chassis will rattle over potholes. The most reliable method is to visit a repair shop and inspect the car on a lift—welding marks on the frame or oil stains around the engine and transmission won't escape an experienced mechanic's eye.

I've bought three used cars and have some experience myself. The first thing to check is the paperwork; look at the green book to see how many times ownership has been transferred, especially the date of the most recent transfer. Open the engine compartment and focus on the screws—if there are signs of tampering on the radiator frame screws or hood screws, be cautious. Check if the interior wear matches the odometer reading; the wear on the steering wheel and gear shift knob can't be faked. Pull the seatbelt all the way out to check for mold, and look for rust on the seat rails, which can reveal a flood-damaged car. Turn on the air conditioning to smell for odd odors, and test the function by switching between hot and cold air. Take it for a drive to see if the steering wheel pulls to one side, and test the brakes by slamming them to feel for vibrations. Check the tire's production date by looking at the last four digits of the DOT code—for example, 2923 means the 29th week of 2023. Bring a paint thickness gauge to measure the paint thickness across the car; factory paint is usually between 80-150um.

Last week, while helping my cousin evaluate a used car, I identified several key points. First, walk around the car three times to check if the headlights show consistent wear. If you can fit your pinky finger into the gap of the front bumper, it indicates prior removal and reinstallation. Inspect the markings in the corners of the glass—the original factory date should precede the vehicle's manufacturing date. Measure tire tread depth by inserting a coin; the national standard requires it to be >1.6mm. Pull out the dipstick—if the oil smells like gasoline, it’s a serious issue. Upon ignition, all dashboard warning lights should briefly illuminate before turning off, which is normal. Test all electronic devices: if the windows make a clicking noise while rolling up/down, the regulator might be faulty, and unresponsive center console buttons are a red flag. Check maintenance records using the VIN, and pay special attention to whether airbags have ever deployed in the accident history.


