Which component must be removed before taking out the valve tappets?

The necessity to remove the camshaft before taking out valve tappets is due to the component's position and function within the engine's architecture. The camshaft controls the opening and closing of the engine's valves and operates in direct conjunction with the tappets (or lifters). Tappets are located directly under the pushrods or rocker arms, which are actuated by the camshaft.

When you need to access the tappets, you must first remove the camshaft because it exerts pressure on the tappets and is positioned above them. Removing the camshaft allows for the necessary clearance and provides access to pull the tappets out without causing damage to other components. This is a common practice in engine maintenance and repair procedures, ensuring that all parts can work freely without obstruction.

While other components such as the oil pan, timing belt, or fuel injectors may be involved in the engine assembly or disassembly process, they do not directly prevent access to the tappets in the same way that the camshaft does.