What Causes the Ticking Sound in a Car Engine?
2 Answers
Reasons for the ticking sound in a car engine: 1. Engine Mount Deterioration or Loosening: If the engine mount deteriorates or becomes loose, the engine may vibrate, and in severe cases, produce a ticking noise. This can be resolved by replacing the engine mount. 2. Overly Rich Air-Fuel Mixture: When the engine's air-fuel mixture is too rich, it may experience difficulty accelerating after starting, uneven operation, black smoke from the exhaust, and a ticking sound. 3. Piston Slap Noise: Due to poor lubrication conditions, excessive wear of the piston and cylinder wall can cause the clearance between them to exceed normal tolerances. During engine operation, the piston skirt impacts the cylinder wall, producing a distinct ticking sound, which is usually more noticeable at idle or low speeds.
Last time when the engine was repaired, the mechanic mentioned that the ticking sound is most likely due to valve clearance issues. Especially for older cars with high mileage, as those small metal parts wear out, the gaps increase, causing a rapid clattering noise during cold starts. If the car has hydraulic lifters, it could be due to insufficient oil pressure or the lifters themselves getting stuck. This kind of sound is very rhythmic, speeding up or slowing down with the engine RPM. I once drove an old Tucson with 150,000 km that had this issue, and replacing the set of valve lifters immediately made it quiet. During inspection, it’s also important to check the timing chain—if it’s stretched, it can produce a rattling sound, and leaving it unaddressed can damage the engine.
