What Causes Engine Abnormal Noise in Volkswagen Magotan?
2 Answers
Engine abnormal noise can be caused by several factors including premature fuel injection timing, fuel injector diesel leakage, piston impacting cylinder walls, excessive piston ring side clearance, impact between valve stem tip and rocker arm, or engine misfire. The specific cause needs to be determined based on different abnormal noise conditions as follows: Abnormal noise caused by rough engine operation, commonly known as "knocking sound". The phenomenon is characterized by strong noise at low speed, clearly audible from over ten meters away, accompanied by difficult starting. After ignition, the engine runs unevenly with rapid coolant consumption. This noise is caused by premature fuel injection timing and requires readjustment of fuel injection advance angle. Engine abnormal noise with certain patterns, sometimes knocking and sometimes backfiring, accompanied by unstable engine speed and intermittent black smoke emissions. This uneven noise is caused by fuel injector diesel leakage. When this occurs, the fuel injector should be serviced. The engine emits "clunking" or "thumping" knocking sounds, particularly noticeable at low speed or sudden speed changes, accompanied by engine oil burning. This noise is caused by excessive clearance between piston and cylinder wall, which increases piston impact on cylinder wall during diesel engine operation. The solution is to replace cylinder liner or piston. Throughout the cylinder block, a "clinking" sound resembling small hammer tapping on an anvil can be heard, becoming more obvious during sudden engine speed changes. This is caused by excessive piston ring side clearance. The piston rings should be replaced, and the piston may need replacement if necessary. "Clicking" or "tapping" sounds around the cylinder head cover, quieter when hot and louder when cold, persisting even when fuel supply is stopped at low speed. The main cause is excessive valve clearance leading to impact between valve stem tip and rocker arm. Valve clearance should be adjusted. Intermittent exhaust gas flow with severe exhaust pipe vibration and clearly audible engine abnormal noise. This is caused by engine misfire.
I've been driving a Volkswagen Magotan for several years, and half a year ago, I encountered an issue with abnormal engine noise. At that time, the car would make a clicking sound during low-speed acceleration, which was particularly sharp, like metal hitting. I immediately conducted some preliminary checks, looked at the oil level, and found it normal, but the noise persisted. Later, I took it to a repair shop, where the technician told me it might be due to a loose or aged timing belt causing abnormal friction, or wear in the connecting rod bearings inside the engine. They mentioned that the EA888 engine in the Volkswagen Magotan is prone to such issues after covering long distances, especially if maintenance is delayed. That time, I replaced the belt and some bearing components, and the noise disappeared. I recommend other owners not to ignore such sounds, as abnormal noises are often early signals of serious engine faults. Early detection can prevent greater losses. Usually, you can listen more to locate the source of the noise. If it comes from the front of the engine hood, check the belt system more; if it comes from the bottom, it might be an issue with internal components, and it's best to seek professional help immediately. After all, safety comes first, and problems at high speeds are too dangerous.
