What are the reasons for loud engine noise at idle?

[LillianaRose]

The reasons for loud engine noise at idle are: 1. The engine oil does not meet the standard or the amount of oil added exceeds the standard, causing unnecessary resistance to the crankshaft rotation, thereby affecting power output; 2. The engine fuel is not fully consumed during frequent use of the car, leading to carbon deposits in the engine; 3. The engine mount pads are aging or loose, affecting the engine and increasing noise. The types of car engines vary depending on different situations: according to power, they are divided into diesel engines, gasoline engines, electric vehicle motors, and hybrid power; according to the intake system, they are divided into naturally aspirated, turbocharged, mechanically supercharged, and twin-charged.