Hi,i dont like to be beaten.been thinking,your engine holds over 11litres of water.are you running 50/50 water,antifreeze?its a large engine and relys on different methods of cooling.You say pump and stat are ok so next step would be to flush rad as suggested as they do lose there cooling efficency over time.if water appears to be free flowing dont replace.check for bleed valves on the highest part of the system,sometimes on coolant pipes.check air temp switch.its summerged in the coolant and as the temp rises the resistance lowers ,if this fails it can cause the fuel mixture to alter which can cause overheating.this will usually show on a diagnostic but not always,finally check condition of the intercooler.if this is blocked air entering the combustion chamber will be very hot making the cooling system struggle.and normlly causes overheating.please let us know how its going.also check to see if it needs pressure filling.this is where a device is placed on top of the coolant tank and the water pressure forces out trapped air,remove dead flys from rad and intercooler.i dont think theres any thing left.hope it helps
mikec
April 2009