NHTSA Complaint #11517156 — 2015 MAZDA CX-9

My check engine light came on. Thought it was the oil needing to be changed. Oil was extra dark and muggy. Also notice antifreeze low. Fill up antifreeze and change oil. 2 wks later antifreeze back down low. Check engine still on. Got it diagnosed with auto scanner and says camshaft sensor. Went to autoshop, mechanic says it's not cramshaft sensor but water tank leak in engine which was picked up by camshaft sensor. I have yet to find out what else is wrong or if my engine needs to be replaced. For sure the water tank needs replacement. I read from others of their car over heating or completely stopped working. I fear this because I have 3 kids and on weekends I drive on the highway for about an hour to get to my destination. This is something dangerous because I don't want to get rear ended or hurt if my car suddenly gives out during heavy traffic.