What Causes the Drumming Sound During Engine Idle?

[ValeriaLynn]

Reasons for the drumming sound during engine idle: Low oil pressure: During idle, the oil cannot adequately lubricate the top valves of the engine, causing the valves to produce noise due to insufficient lubrication. The noise will disappear once the engine is fully lubricated. Faulty carbon canister solenoid valve: A small amount of exhaust gas from the fuel tank is recirculated into the combustion chamber for burning. During this process, it passes through the carbon canister solenoid valve. If this component is aged or damaged, it can produce abnormal noises. Piston slap: If the noise disappears or weakens after the engine warms up, it indicates piston slap, which requires professional attention at a repair shop or 4S store.