2011 LEXUS ES350 Engine Problems

MY LEXUS ES 350 ENGINE SHUT OFF WHILE DRIVING ON HWY W/O PRIOR NOTIFICATION OF ANY ERROR MESSAGES. MECHANIC SAID DIAGNOSTICS POINTED TO COOLING SYSTEM ERROR - WATER PUMP RELATED. THE PUMP WAS REPAIRED. CAR TEMP LIGHT WOULD FLUCTUATE FROM COLD TO HOT BACK TO COLD. MECHANIC SAID COOLING SYSTEM APPEARS TO BE FUNCTIONING BUT SENSORY GAUGE STILL FLUCTUATING. DEALER MECHANIC SAID WATER PUMP NEEDED TO REPLACED BUT THIS WAS ALREADY DONE. THEN INDEPENDENT MECHANIC INFORMED ME THAT ENGINE OVERHEATED AND WARPED. NOW CAR NEEDS ENGINE. CAR INITIALLY SHUT DOWN ON HIGHWAY W/O WARNING.

LEXUS INBOX X [XXX] <[XXX]@GMAIL.COM> 10:23 AM (0 MINUTES AGO) TO ME I OWN A 2011 LEXUS ES 350. ON 12/10/2015 I WAS PARKING IN A CHURCH PARKING LT WHEN SUDDENLY MY CAR ROARED LIKE AN AIRPLANE AND SURGED UP A HILL THROUGH AN IRON GATE AT A CEMETERY, DOWNING A STONE PILLAR AND FINALLY COMING TO A STOP ON TOP OF A HEADSTONE. I CANNOT DESCRIBE THE SHEER PANIC I EXPERIENCED. MY FIRST THOUGHT WAS THANK GOD NO ONE WAS IN FRONT OF ME. THE PREVIOUS DAY I PICKED UP MY 5 YR OLD GRANDDAUGHTER AT HER ELEMENTARY SCHOOL. CHILDREN COULD HAVE BEEN KILLED!!!! I CAN NEVER DRIVE THIS CAR AGAIN. I BELIEVE IT WILL BE TOTALED ANYWAY. IT'S AT EDDIE'S AUTO BODY IN MOODUS, CONNECTICUT. I RETIRED 2 1/2 YRS AGO FROM P&W AIRCRAFT AS A PERFORMANCE ENGINEER TO BUY THE CAR OF MY DREAMS WHICH TURNED OUT...