The Causes of a Continuous Tapping Sound From the Engine

When you start your car engine in the morning, sometimes you will hear some sort of tapping sound coming from the engine. The sound will disappear after the engine has warm up. This is quite normal on some cars but if the tapping sound continues as long as the engine is running, then there is something wrong with the car engine.

As the engine rpm increases, the sound will also increases and when the engine rpm slows down, the tapping sound also decreases. If you open the hood, you can hear that the loudest sound comes from the top of the engine.

Stuck hydraulic lifters caused most of the sounds that you hear coming from the top of the engine. The hydraulic lifter or also known as hydraulic tappet or hydraulic lash adjuster is designed to take up the normal expansion and contraction during the heating and cooling of metals in the engine.

The lifter is also designed to maintain zero valve clearance in an internal combustion engine where it ensure the valve train always work with zero clearance for a quieter operation and at the same time to ensure periodic valve clearance adjustment is not required.

If one or more of the lifters are stuck or jam, tapping sound will occur. If the sound lasts for a couple of seconds or minutes, then frequent oil change could free up the jam lifter. If the sound continues, then the lifter will have to be replaced.

If you notice that when the engine is giving out tapping sound and comes with heavy vibration at idle or on heavy load, one of the valve push rods or rocker arms has broken. To confirm this, get you mechanic to remove the rocker arm covers to check on the rocker arms, push rods, and the valve stems. Normally by replacing the rocker arms and bolts, the tapping sound problem can be repaired.

If the tapping sound is accompanied by a muffled backfire when you accelerate, there is a high possibility that the engine camshaft has damage. This require major repair because you also need to replace all the hydraulic lifters. Make sure that your mechanic checked the camshaft thoroughly and confirmed faulty before you start the repair.

If the tapping sound is due to broken rocker arm or push rod, you car will suffer from fuel wastage, poor performance and also high emissions of Carbon Monoxide to the atmosphere.