Question

Technician A says to check coolant level in the overflow reservoir, and that it should be between the hot (high) and cold (low) marks. Technician B says to never open the radiator or reservoir pressure cap on a hot engine. Which technician is correct? A. Technician A only B. Both Technicians A and B C. Technician B only D. Neither Technician A nor B

Answer 1

The correct option is B.
Both technicians were correct. The coolant level of the overflow reservoir of vehicle ranges between hot and cold. To be on the safe side, the coolant level should always be checked on a cold engine. For a cold engine, the value obtained for the coolant level will be the true value, because the engine has not yet undergo expansion. It is dangerous to open a hot radiator, because the hot pressure of the engine can spill the hot water from the radiator all over one's body and this can cause serious burns.