Question 432Motor Plants - Assistant Engineer

The correct answer is D) measuring the cold valve clearance between components "C" and "D". The valve clearance, which is the gap between the valve stem and the rocker arm, needs to be checked and adjusted as part of normal maintenance on the valve mechanism. Measuring the cold valve clearance between components "C" and "D" is the appropriate procedure, as this ensures the valve is opening and closing properly. The other options, such as adjusting the valve at points "D" or "E", or changing the tappet clearance, are not the correct maintenance steps for this particular valve mechanism.