1. Low Oil Pressure: Inadequate oil pressure can cause engine components to lack proper lubrication, leading to metal-on-metal contact and knocking sounds. Check the oil level and condition and ensure the oil pump is functioning correctly.
2. Worn Engine Bearings: Worn or damaged engine bearings can cause knocking noises as the crankshaft and connecting rods move within the engine block. This issue can worsen as the engine warms up and the oil thins out.
3. Piston Slap: Worn piston rings or excessive clearance between the pistons and cylinder walls can result in piston slap, a knocking sound that occurs when the pistons change direction at the top and bottom of their stroke.
4. Spark Knock (Detonation): This occurs when the air-fuel mixture in the engine ignites too early, causing a sudden, uncontrolled combustion that produces a knocking noise. It can be caused by low-quality fuel, incorrect ignition timing, or engine deposits.
5. Worn Timing Chain or Belt: A worn or loose timing chain or belt can cause the camshaft and crankshaft to be misaligned, resulting in knocking sounds as valves open and close at the wrong times.
6. Faulty Lifters or Pushrods: Hydraulic lifters or mechanical lifters that are malfunctioning or damaged pushrods can cause knocking noises as the valves open and close.
7. Failed Connecting Rod: A broken or bent connecting rod can cause severe knocking sounds and engine damage. This is a serious issue that requires immediate attention.
8. Bad Fuel: Low-quality or contaminated fuel can cause knocking sounds due to poor combustion or deposits forming in the engine.
