Who is correct about testing a radiator cap and thermostat?

When testing a radiator cap, it’s important to verify that it holds pressure properly. A radiator cap has a specific pressure rating, which ensures that the cooling system can maintain the appropriate pressure. If the cap does not hold this pressure, it can lead to overheating or coolant loss, as the system will not reach its designed temperature and pressure levels. Proper testing involves using a cap tester to check if the cap maintains pressure without leaking.

For the thermostat, an accurate test involves checking its operation at specific temperatures. The thermostat should open at the designated temperature to allow coolant to flow through the engine and radiator, preventing overheating. Testing can be accomplished by submerging the thermostat in water and heating it while monitoring the temperature closely to see if it opens and closes as intended.

By understanding these processes, it becomes clear that the correct answer emphasizes the correctness of Technician A's understanding and methodology regarding the testing of the radiator cap and thermostat.