What Does Engine Piston Slap Sound Like?
2 Answers
Engine piston slap is a crisp, rhythmic metallic knocking sound that varies with temperature changes. The causes of engine piston slap include: 1. Excessive wear between piston and cylinder leading to oversized clearance; 2. Incorrect piston installation orientation or piston deformation; 3. Poor lubrication of cylinder walls; 4. Bent or twisted connecting rods; 5. Clogged oil passages; 6. Severe carbon buildup in combustion chamber; 7. Excessive fuel injection advance angle; 8. Overly rapid combustion of air-fuel mixture causing excessive cylinder pressure; 9. Overly thin cylinder gasket or excessive wear on cylinder block top surface, resulting in increased compression ratio in diesel engines.
Speaking of engine knocking sounds, I once heard it when accelerating uphill in my old car. That crisp, rhythmic tapping noise was really alarming, like a small hammer rapidly hitting an iron bucket. It was especially noticeable at high speeds, as if the engine was protesting. Later, I found out it was caused by detonation—improper fuel combustion impacting the piston walls, leading to this metallic collision noise. If ignored, the piston rings or cylinders could be damaged, or even the engine ruined. I must remind my friends: if you hear this sound, don't push through it. Get a mechanic to check and adjust the ignition timing or fuel quality as soon as possible to avoid breakdowns or accidents on the road. Regular checks on engine smoothness are crucial to avoid costly major repairs.
