What Causes the Constant 'Deng Deng Deng' Noise When the Car Reaches 40 MPH?
2 Answers
When the car reaches 40 MPH, there is a constant 'deng deng deng' noise, which is due to engine malfunction. Below are the detailed explanations: 1. Engine Noise: Engine noise indicates that the technical state of a certain engine component has changed. This is mainly caused by excessive wear of some parts or improper assembly and adjustment. Some noises can even predict potential catastrophic damage to the engine. Therefore, when the engine produces abnormal noises, it should be repaired promptly to prevent further damage. It is important to note that if the noise originates from inside the engine, most car owners cannot resolve it themselves, and it is best to send the vehicle to a professional repair shop. 2. Engine Classification: An engine is a machine that converts other forms of energy into mechanical energy, including internal combustion engines (reciprocating piston engines), external combustion engines (Stirling engines, steam engines, etc.), jet engines, electric motors, etc.
Last time my car made a rattling noise at 40 mph, and after a long inspection, I found it was a tire issue. The wheel balance weights had fallen off or the dynamic balance wasn't done properly, causing resonance and a thumping sound at certain speeds. Another possibility is wheel rim deformation, especially for cars that have scraped against curbs while parking—even a slight bend in the steel rim can cause rhythmic noises. During the check, I tried lifting the car and spinning the wheels to listen for any abnormal sounds. For simpler issues, you can even feel the tires yourself to check for bulges or punctures. Uneven tire wear is also common, like when the front wheel alignment is off, causing the tread to wear unevenly and produce clunking noises. Ignoring these problems is dangerous, as increased tire noise on highways also leads to higher fuel consumption. My friend once overlooked this issue, resulting in a tire blowout during a long trip—luckily, no one was hurt. Later, he spent over 2,000 yuan replacing the entire set of tires and realigning them before the noise finally stopped.
