Low oil levels can cause the engine to knock as there is insufficient lubrication to properly silence and cushion metal parts like pistons and piston rods.
2. Worn or damaged engine components:
Worn or damaged components like faulty piston rings, or loosened bearings, can cause the engine to knock as the components become loose or unable to absorb the mechanical stress during the combustion cycle.
3. Oil pump failure:
An oil pump that is not working properly or has a weak suction system may result in lower oil pressure, leading to knocking sounds due to reduced lubrication.
4. Faulty hydraulic lifters:
These components are responsible for adjusting valve clearances and worn-out or malfunctioning lifters can cause a tapping or clattering knocking noise.
5. Pre-ignition or detonation:
These problems occur when the air/fuel mixture ignites too early due to higher compression ratios, carbon buildup, or poor fuel quality. This abnormal combustion process can lead to an audible knocking noise.
6. Loose or damaged spark plugs:
Loose spark plugs or incorrect spark plug heat ranges can cause abnormal combustion, leading to engine knocking.
7. Carbon build-up:
Carbon accumulation on the piston crown or valves' surface results in higher local temperature and pressure that could lead to knocking due to premature ignition.
8. Faulty fuel injector:
Faulty fuel injectors can cause poor fuel atomization, resulting in incomplete combustion and engine knocking.
9. Bent connecting rod:
A bent connecting rod can lead to excessive play between the piston and the cylinder wall, resulting in a knocking noise.
10. Crankshaft bearing failure:
This is a severe mechanical issue where the connecting rods' bearing surfaces on the crankshaft may wear down or become damaged, leading to a consistent knocking noise.
It is important to have the specific reason behind the engine knocking sound diagnosed by a professional mechanic to prevent potential engine damage and ensure a proper repair.
