My '02 V70 T5 has this week started warning me of a low coolant level when I start it up in the morning. The first time I turned the engine off, raised the hood, and visually checked the coolant level. The level was, in fact, below the "MIN" line in the tank. I recalled that coolant is stored throughout the system and figured that the sensor was essentially reading the level in the tank.

This seemed in fact to be the case. I drove about a block and the warning light went away. But it's now happened the last three mornings. Is this anything to worry about? Is it simply a matter of topping off the coolant level?

Appreciate any insights.