Why is the engine noisy when starting a cold car? Why is the engine noisy when starting a car?

When we drive, we usually warm up the car first, and then we can start driving after the car self-check is completed. Sometimes the sound is very loud when starting a cold car, but the sound becomes much quieter after warming up for a while. This is actually a relatively normal situation. What is the specific reason?

Why is the engine noisy when starting a cold car?

It is normal for the engine to make a loud noise when it is cold started and then become quieter after a while. This is mainly caused by the engine warm-up mechanism. The first reason why the car makes a loud noise when it is just started is the high speed. When the car is cold started, the speed will be higher, so that the engine can quickly enter the best working state, and then the three-way catalytic converter can enter the best working state as soon as possible.

Inadequate lubrication and protection. We know that engine oil has many functions, including lubrication, sealing, protection, cooling, etc. When the car is cold-started, the lubrication system cannot be established instantly, so some parts are dry rubbed, so the noise will be louder.

Why does the car make a loud noise when it starts?

It is completely normal for the car to make a loud noise when it is just started. The sound is very loud when the engine is ignited, but you must understand that the sound at this time is produced by multiple links together, and the sounds are in a superimposed state, so the ignition moment is often a loud bang; however, after the vehicle is started, only the engine-related components are running, and the sounds of other parts stop, so the sound gradually becomes smaller. Moreover, as the car warms up and the speed continues to decrease, the sound will naturally become smaller!

What's the matter with the knocking sound when starting the engine from cold?

This is a normal phenomenon.

Because the vehicle has been stationary for a long time, the lubricating oil inside the engine is deposited at the bottom of the engine. During a cold start, the oil at the bottom of the engine cannot quickly reach the top to lubricate the various components. At this time, the various components on the top are basically in a semi-lubricated state, and the knocking sound between metals is much louder than usual.

Related News

Yesterday (February 13), the China Association of Automobile Manufacturers announced my country's automobile production and sales data for January 2020 in the form of an online press conference. In January, according to the statistical data of key enterprise groups, my country's automobile production and sales were 1.783 million and 1.941 million respectively, down 33.5% and 27.0% month-on-month, and down 24.6% and 18.0% year-on-year respectively.