What are the reasons for loud engine noise at idle?
2 Answers
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.
Increased engine noise at idle is something I've encountered several times. It's usually related to aging engine mounts - when the rubber cracks, the vibration damping effect disappears, and engine vibrations are directly transmitted to the body. The belt system is another common noise source; loose alternator belts or AC belts can cause squeaking sounds. Carbon buildup is often overlooked - deposits near fuel injectors can cause unstable combustion of the air-fuel mixture, producing a knocking sound. Another issue is exhaust manifold gasket leaks, where escaping exhaust gas creates a whistling noise. These faults are often accompanied by steering wheel vibrations. The most troublesome situation occurs when the entire mounting rubber collapses in older vehicles, requiring complete replacement. Regular inspection of engine mounting components is recommended.
