2005 FORD F-450 SD Engine And Engine Coolingcooling System Problems

I OWN SEVEN 2004 AND 2005 FORD F-550 AND F-450 TRUCKS WITH DIESEL ENGINES THAT I USE FOR MY BUSINESS. EVERYONE OF THESE VEHICLES HAS BROKEN DOWN ON THE SIDE OF THE ROAD WITH THE SAME PROBLEM-LEAKING HEAD GASKETS. HERE IS A LIST OF THE MILEAGES THAT THE FAILURES OCCURRED: VEHICLE #1 - 96,914 & 100,023 VEHICLE #2 - 114,963 VEHICLE #3 - 106,884 VEHICLE #4 - 69,620 & 109,635 VEHICLE #5 - 69,497 VEHICLE #6 - 58,537 & 81,433 VEHICLE #7 - 89,146 & 90,000 & 147,571 THE FORD DEALERSHIPS THAT HAVE REPAIRED MY VEHICLES ACKNOWLEDGE THAT THERE IS A PROBLEM WITH THE DIESEL ENGINES IN THESE MODEL YEARS BASED ON THE NUMBER OF REPAIRS THEY HAVE PERFORMED. NOT ONLY MINE BUT MANY OTHERS. BUT FORD MOTOR COMPANY DENIES THAT THERE ARE ANY PROBLEMS WITH THEIR ENGINES. OBVIOUSLY FORD IS TRYING TO HIDE THE PROBLEM. PLEASE HELP. *TR