Where do you check the coolant level when the RB-M 45 is at import?

Checking the coolant level in the expansion tank is the correct procedure when conducting maintenance on the RB-M 45 while it is at the dock. The expansion tank is designed to accommodate variations in coolant volume that occur due to temperature changes during engine operation. It provides a visual indicator of the coolant level and ensures an adequate supply of coolant to the engine.

When the vessel is at import, checking the expansion tank allows for easy access and observation. This action ensures that the coolant system is functioning correctly and helps to prevent overheating, which could lead to engine damage.

Other options may not provide the most effective means of checking the coolant level. For instance, while the recovery tank can collect overflow coolant, it is not the primary place for checking the level during routine maintenance. The sea chest is involved in the vessel's cooling systems but is not a location for checking coolant levels. The engine room itself, although housing the engine and related equipment, doesn’t specifically offer a designated point for coolant level inspection like the expansion tank does.