What do yo know about an 09 6.4 Ford Diesel?

While I would agree paramedics are hard on vehicles. I would suggest this is from hours or idiling cool (an ambulance should never be cold) full throttle starts and undercooling. Our suspicion is that the vehicles were resting at a higher temp than was speced resulting in the oil being too thin for proper lube and retention by the rings resulting in severe cylinder wash and excessive oil use. All 3 were 25k km in or more and the rest some still in service were driven to 200k or more with constant attention to oil levels etc. that's deff a towing motor