What is the sound of a car making a scratching noise?

[BennettAnn]

Car making a scratching noise is the sound produced by engine oil, possibly due to reasons related to the oil. Inferior quality oil, prolonged intervals without oil changes, or insufficient oil levels can easily increase friction between the valves and guides, as well as in components like hydraulic lifters, thereby amplifying various noises within the engine. Relevant information about engine oil is as follows: 1. Introduction: Engine oil, also known as engine lubricant (English name: Engine-oil), with a density of approximately 0.91×10³ (kg/m³), serves to lubricate and reduce wear, assist in cooling, seal against leaks, prevent rust and corrosion, and provide shock absorption and cushioning for the engine. It is hailed as the 'blood' of the car. 2. Composition: Engine oil consists of two parts: base oil and additives. The base oil is the main component of lubricating oil, determining its basic properties, while additives compensate for and improve the shortcomings of the base oil's performance, endowing it with certain new properties, making them an important part of lubricating oil.