Why does the Haval H6 make loud noise when accelerating?

[LeEvan]

Haval H6 makes loud noise when accelerating mainly due to the following reasons: Use of inferior engine oil: Since most new cars are initially filled with fully synthetic oil along with grinding agents, which have low viscosity and high quality. After the first maintenance, if replaced with lower-quality oil, the higher viscosity will cause additional friction during high-speed engine operation, thus possibly increasing engine noise. Cold start or low temperature causing louder engine noise: After the vehicle has been parked for a long time, the lubricant mostly flows back to the oil pan. A cold start cannot ensure the immediate formation of an oil film, and dry friction combined with high idle speed during cold starts results in louder engine noise during this period. Similarly, if the engine's water temperature is insufficient due to low ambient temperature, it will lead to higher idle speeds. If the engine rubber hardens and loses elasticity, slipping may occur during operation, further increasing engine noise. Carbon buildup from prolonged driving: Carbon buildup is inevitable during car operation. Areas prone to carbon buildup include the throttle valve, intake manifold, intake valves, and fuel injectors. When carbon buildup in these areas reaches a certain level, it will cause the engine noise to increase, especially noticeable during acceleration. Fuel quality issues: If the fuel quality is poor, it can easily cause engine knocking. While slight knocking may benefit power enhancement, erratic knocking can lead to a series of adverse effects, with increased engine noise being just one aspect. Knocking can also worsen fuel consumption and cause engine misfires and vibrations.