Seems that these machines run full tilt at 16klms/hr 15hrs a day.We have 35 on our floor all around 4000-9000 hrs 85% have had a headgasket.I have tried an infra-red gun that seemed to show only a slight indication of a possible thermostat failure.We just had a machinist come in do various head/block checks he took a headbolt with him saying that our multilayer steel gaskets might need a different torque and maybe different bolts??