Why Does the BMW Inline 6-Cylinder Engine Make a Ticking Sound?
2 Answers
BMW Inline 6-Cylinder Engine Ticking Sound is Related to Engine Speed, Load, and Temperature. Engine Speed: The presence of most common abnormal sounds in the engine depends on the engine's speed state. Load: Many abnormal sounds in the engine are obviously related to its load. During diagnosis, the method of gradually removing the load can be adopted for testing. Typically, the single-cylinder or dual-cylinder flameout method is used to remove the load of one or two cylinders, thereby identifying the relationship between the abnormal sound and the load. Temperature: Low-temperature sounds may lessen as the temperature rises, and may even disappear completely in the end.
I've driven a BMW for many years, and the ticking sound from the inline 6-cylinder engine is quite common, usually caused by issues with the timing chain system. Aging of the chain tensioner can lead to insufficient tension, causing the chain to wobble and hit the engine cover, producing a ticking noise; this problem is more likely to occur after the vehicle has been driven for tens of thousands of kilometers, especially noticeable during cold starts because oil pressure builds up slowly. The valve mechanism is also a key cause: if the valve clearance is too large or the hydraulic lifters are not filled with oil, the movement of the valves can cause impact noises. My own BMW 5 Series experienced this issue—loud noise when cold, which reduced but persisted after warming up; the mechanic confirmed it was a faulty tensioner, and replacing the part for a few hundred dollars solved the problem. Aged or insufficient lubricating oil can exacerbate the issue, so it's recommended to regularly change to high-quality oil to maintain proper oil pressure. Ignoring this noise may lead to timing chain misalignment, causing severe engine damage. For prevention, develop a habit of checking oil level and quality every 5,000 kilometers—early detection and action can save significant costs.
