The engine was not checked before the car was removed, it was found to have been removed, and it was not clear for three months that a 4s shop had been found. In 2025, a vehicle complaint platform counted over 13,000 complaints relating to "new engine abnormalities", of which about 20 per cent related to engines having been dismantled. Today you can tell the five most practical ways to check a car, and you can do it 10 minutes before you lift it。
See if there's any unusual signs
Open the hood of the engine and look first at the combination of the cask and the gas chamber. The brand new engine bolts have original rectangular marking paints with uniform colours and no scratches. If some of the bolted paints are polished or the colours are not consistent, there are traces of leaks of sealed glue on the combined face, indicating that it was opened. Focus on oil bolts on the side of the warp axle and must leave marks after the six-angle of the 10 mm mark is the most easily ignored evidence of demolition。
Re-inspect pipes and beams. The original plant was equipped with a well-arranged piping line and a plug-in covered with lead-proof seals. If there are re-plugged scratches at a beam entry, or if the route is manifestly different from the side, the rate is probably removed and reloaded. Taking a flashlight from the side, the marks on the metal surface are clearly different from the state of the plant and can be seen in seconds。
Listen to the engine
Two minutes after the start of the cold car, the engine will be idle. The normal operating sound is a flat humming, and the speed gauge is stable between 800 and 900. If you hear the sound of a metal impact, the sound of a sharp glittering belt, or the sound of a glitch, it means that the internal gap is not right. Let the 4s store technician listen to you in person. Don't let him use the word "normal"。
Keep the speed to 2500 and 4000, respectively, for 10 seconds and listen to the noise. It is normal that the high-turning engine after major repairs may be a little more boring than the new car. But if the sound is too small and the speed of the turn is too high, it suggests that the pressure of the cylinder is uneven and that the piston rings or gas doors of a tank may not have been installed. In the second half of 2024, multiple new models were called back in bulk because of the lack of air gap adjustments, and it would be better for you to confirm that again。
Check tail color and status
The engine's water temperature rises to 90 degrees and stretches with a white paper towel to the vent for three to five seconds. Normal tails are colorless, with a little light black powder on the paper towel. The visible blackening of the paper towel indicates inadequate combustion; oil stains are impregnated to indicate burning oil; and the smell of the nose of white beads may be a chain of anti-frozen fluids into gas cylinders. Don't look in the cold car. Cold car white smoke is normal condensed water, not counting。
See if there's any blue or blue gray smoke in the vent. Blue smoke is a typical expression of engine oil, often in the wear of piston rings or the ageing of gas-gate seals, and in 2023 a brand of 1. 5t engines was the subject of a concentrated complaint. Let the mechanic pull the speed to 3,000 for 30 seconds, and if the tail color is clearly abnormal, the problem will not be hidden. You just stand in the air and watch. You don't have to smell it in the pipe。
Watch key data on dashboard
After the car, look at the water temperature table, which normally floats at 90 degrees above and below, and the pointer does not swing sharply. Then look at the rotation schedule, the glitch should be steady around 800 and not more than 50 volts up and down. The internal sealing or sensor problems are indicated if the speed of rotation is not high or low, or if the temperature of the water is delayed to reach the normal zone. Turning air conditioners to their maximum, with a warm wind and a large light, normal speeds can only rise up by 100 to 150 and exceed 200 turns。
Press the multiple functions key of the wheel to pull out the malfunction page. Even if the dashboard does not have a failure light, the technician should read the entire system history code with a diagnostic device. In major repairs, if the wrong sensor or line is not plugged in, it leaves a "historical code" that does not light. The focus is on p0300 to p0308 (fire in gas cylinders) and p0171 (malgamated gas), which basically indicate that the engine was operated inside。
Road testFeel the power output
Let the mechanic drive, you ride the side. From 0 to 60 yards, feel whether the gas-gate response is linear or not, or if it's a "one-on-one" setback. The power should be steadily exported from the 200 to 250 roundabouts, if there is a clear delay or if there is a sudden "floating" that means that the air-saving doors or nozzles are not fixed. Up to 120 yards, listening to the sound of the engine is even, and there's no loss of speed in a cylinder。
Find a straight-up ramp and hold the d block from 30 yards. A normal four-cylinder engine of 2,500 turns or more should be able to climb the slopes with no apparent deceleration. If the speed is pulled up but not at the speed, and the engine sounds boring, it may be exhaust congestion or turbo work unusual. When brakes are made, care is taken that the power of the brakes is even and that the half-axis or speed differentials may pass by if they are to the right or to the left。
FlipMaintenance recordsCheck the source of the parts
The 4s store was asked to show the complete pdi records and maintenance manifests of the vehicle. It's important to see if there's a project like "engine dismantling" "gas tank compression" "replacement." if it's only "the appearance check" and there's no record of demolition, it's probably not moving. On the other hand, there's an acoustic check in the list and an "replace the gasket." you're gonna have to be alert to the store to bring up the sheets and maintenance images。
Check the branding network or the dealer system to confirm whether it was the original plant. The technicians were asked to show the batch numbers of oil filters, air filters, spark plugs, and check them with the sheet records. In 2025, the ministry of industry and communications requested the 4s store to retain the maintenance image and accessories trace data, which you are entitled to. If the other party refuses to provide it on the grounds of "system failure", the signal itself is an indication of the problem, and you can simply refuse to pick up the car。
Will you open the hood before you bring it up, or will you just sign it on the fourth s? Welcome to the comment area to talk about your car-testing experience, and if you think it's useful, it'll be forwarded to your family and friends who are taking the car。
