Final answer:
(B) the amount of pressure listed on the radiator cap. The correct procedure for pressure testing a cooling system is to apply the amount of pressure listed on the radiator cap, as this corresponds to the system's designed maximum pressure.
Step-by-step explanation:
When performing a pressure test on a cooling system, the technician should apply the amount of pressure listed on the radiator cap. This is because the pressure rating on the cap corresponds to the maximum pressure the system is designed to handle without causing damage or leaks. Exceeding this pressure might result in damage to the cooling system or inaccurate testing results. Therefore, option (B) is correct.
Applying 5 pounds of pressure with the engine running or applying 5 pounds more pressure than listed on the radiator cap could damage the system, and adhering to the danger zone on the pressure gauge may exceed the cap's rating. It is crucial to follow the manufacturer's specifications and not to exceed them to ensure the integrity of the cooling system.