What Causes Idling Noise in BMW 5 Series?
1 Answers
BMW 5 Series idling noise The reasons for engine idling noise are as follows: Timing chain elongation, tensioner pressure relief, balance shaft wear: Timing chain elongation is generally caused by metal fatigue. After prolonged driving, combined with the high-temperature working environment of the timing chain, it is easy to produce chain elongation, resulting in noise. Camshaft, crankshaft, connecting rod bearing wear: If the vehicle is filled with inferior engine oil, excessive sludge may form in the engine, blocking the lubrication oil passages and preventing the oil from reaching the components that require lubrication and cooling. This can lead to wear on the camshaft, crankshaft, and connecting rod bearings, causing noise. Additionally, if the engine lacks coolant, resulting in excessively high engine temperatures, the above phenomena can also occur. In severe cases, it may even lead to cylinder scuffing or bearing seizure. Increased variable timing wheel clearance: Variable valve timing can adjust according to engine speed and operating conditions. It generally uses hydraulic control to adjust the internal rotor of the camshaft timing gear, achieving a certain degree of advance or delay. If the internal rotor of the variable timing wheel becomes stuck or the oil chamber wears out, it can lead to increased clearance and noise. Excessive valve clearance, rocker arm damage: The rocker arm is the lever mechanism that presses the valve, and the valve clearance is mainly controlled by the hydraulic lifter. Damage to either component can cause valve noise.
