If a coolant container is part of a pressurized system, you should check the coolant level with the engine hot.

If a coolant container is part of a pressurized system, you should check the coolant level with the engine hot.

• A. Cold engine
• B. Hot engine
• C. Engine off
• D. After driving 30 minutes

Answer: (B)

In a closed, pressurized cooling system, coolant expands when it’s hot, and the level you see in the reservoir reflects that hot, under-pressure condition. Therefore, to get an accurate reading of the actual operating level, you check the coolant while the engine is hot. Checking when cold can mislead you because the coolant volume shrinks as it cools, making the level appear lower than it will be when the engine is running. Remember not to remove the cap while the system is hot; wait until it’s safe or simply observe the level on the reservoir.

In a closed, pressurized cooling system, coolant expands when it’s hot, and the level you see in the reservoir reflects that hot, under-pressure condition. Therefore, to get an accurate reading of the actual operating level, you check the coolant while the engine is hot. Checking when cold can mislead you because the coolant volume shrinks as it cools, making the level appear lower than it will be when the engine is running. Remember not to remove the cap while the system is hot; wait until it’s safe or simply observe the level on the reservoir.