Question 493Motor Plants - Assistant Engineer

You are correct, the answer is A) excessive valve lash. A clicking sound in the valve compartment of a diesel engine is typically caused by excessive clearance or "lash" between the valve stem and the rocker arm or pushrod. This allows the valve to move up and down without proper control, resulting in the characteristic clicking or tapping noise. The other options (B - worn wrist pin, C - worn connecting rod bearings) would not directly cause a clicking sound in the valve compartment. These issues would likely result in different engine noises or performance problems.