2015 Mazda CX-9 UNKNOWN OR OTHER,ENGINE

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.

WHILE DRIVING MY 2015 MAZDA CX-9 ON A VERY BUSY INTERSTATE, THE CHECK ENGINE LIGHT APPEARED ON THE DRIVER PANEL. I WAS TRAVELING WITH MY VERY YOUNG CHILDREN, AGES 4 AND 20 MONTHS. APPROXIMATELY 10 MILES LATER, I STARTED HEARING A RATTLING SOUND UNDER THE HOOD. SHORTLY THEREAFTER, MY CAR STALLED OUT AS I ENTERED MY SUBDIVISION. MY HUSBAND HAD TO PUSH THE CAR TO OUR DRIVEWAY. I CALLED AAA THAT SAME DAY AND HAD THE CAR TOWED TO THE DEALERSHIP THAT SERVICES THE VEHICLE. I WAS TOLD THAT THE WATER PUMP NEEDED TO BE REPLACED AND WAS QUOTED A PRICE TO FIX THE ISSUE. LATER, I WAS TOLD THAT AFTER FURTHER INSPECTION BY THE DEALERSHIP THAT THE COOLANT MIXED WITH FLUIDS AND THE ENGINE NEEDED TO BE REPLACED. I WAS QUOTED OVER $7000 TO COMPLETE THIS WORK. DURING THE COURSE OF MY RESEARCH, I HAVE LEARNED THAT A LOT OF MAZDA CUSTOMERS WHO HAVE THIS MODEL VEHICLE EXPERIENCE THIS ISSUE QUITE FREQUENTLY. I CALLED MAZDA CUSTOMER CARE AND WAS TOLD THAT MAZDA IS NOT ELECTING TO TAKE RESPONSIBILITY FOR THIS ISSUE. I WAS FORTUNATE THAT I WAS ABLE TO ARRIVE TO MY SUBDIVISION WITHOUT INJURING MY CHILDREN OR SELF, BUT THIS IS A SAFETY ISSUE THAT COULD RESULT IN THE LOSS OF LIVES IF NOT CORRECTED IMMEDIATELY.