The radiator level should be checked from the "hot" and "cold" levels in the run off tank. You looked in the right place to begin with. For such a large truck mine seems to heat just as well as any other car or truck I have owned. There are several components to the heating system and heater core. There are also several thermostats and one could be malfunctioning not allowing hot coolant to flow through the core where the blower is located. If it seems like it is not heating like it use to you should have it looked at.aquaranti said:even though the temp gauge is in good territory the heat still takes a while to come out hot, controls are set to hot all the way in the red area . when I rev engine it seems to get hotter out of the vents but when at idle it cools down. I checked the anti freeze in the bottle and it is at the right mark, however when I opened the radiator cap I noticed that the level was down, could I need anti freeze in the radiator? my armada is a 2004 le with 20000 miles on it.