I have (5) OM 400's in service with lowest use engine at 9,000 hours and highest use engine at 19,500 hours. I have never performed any internal repair work on any of these engines. They have been serviced at 200 hour intervals. Does anyone have any idea of the life expectancy for these engines? All these engines are in all terrain cranes with a road weight of 106,000 lbs on 4 axles up to 140,000 lbs on 5 axles.