When your coolant light comes on, it means your coolant is pretty much depleted. Continuing to drive without coolant can lead to problems like the engine overheating or blown gaskets. You shouldn't drive for very long with your coolant light on; instead, pull off the road and let your engine cool down. Then refill the coolant reservoir as soon as possible. Then your best best is to head to an auto garage to determine why your coolant is low, according to Autoblog.com.