Well if you started at the low level and added 1/2 a beer can full of coolant, that is the level it should rise to at normal operating temps. Drink the beer first before using the can for coolant measurements, and don't put beer in the VFR. If you were to add 3/4 of a beer can (might need a second can of beer for this) of coolant from low, that is the maximum level it should rise to when very hot. See, science and beer do mix. My 5th gen manual tells me to fill the reservoir to the upper line when cold.