What are the symptoms of abnormal engine noise?

[TeaganLee]

Symptoms of abnormal engine noise include: 1. Piston slap noise; 2. Piston pin noise; 3. Crankshaft main bearing noise. Causes of abnormal engine noise are: 1. Cold start noise due to unsuitable engine oil; 2. Incorrect belt tension; 3. Poor fuel quality or incorrect fuel grade; 4. External engine factors; 5. Insufficient oil pressure preventing the timing chain from functioning properly; 6. Crankcase ventilation leakage. Solutions for abnormal engine noise include: 1. Check the fuel grade being used; 2. Inspect the engine temperature; 3. Examine the engine's air-fuel mixture ratio; 4. Verify the connection of the engine's negative ground wire; 5. Check for carbon buildup in the engine combustion chamber; 6. Inspect the ignition timing.