Why does the engine sound louder in cold weather?

[StFelix]

The reasons why the engine sounds louder in cold weather are: 1. After the car has been parked for a long time, the engine oil flows back to the oil pan at the bottom of the engine; 2. Before the engine reaches its operating temperature, the fuel supply system cannot effectively vaporize gasoline completely due to low temperature; 3. In cold conditions, gear oil flows to the lower part of the transmission; 4. The engine mount rubber is aged or loose. The methods for engine maintenance are: 1. Regularly change the engine oil and filter; 2. Use lubricating oil of appropriate quality grade; 3. Regularly clean the radiator; 4. Regularly replace the air filter, oil filter, and fuel filter; 5. Maintain good crankcase ventilation and clean it regularly; 6. Regularly clean the fuel system.