Why may exhaust temperature of all cylinders rise too high?

Check following most probable causes:

1. Boost air temperature too high
   1. Boost air cooler cooling water temperature too high.
      Check the cooling water system and adjust water temperature.
   2. Boost air cooler cooling water volume.
      Check cooling pump capacity and presence of air.
   3. Fouling of boost air cooler (cooling water side & air side).
      Clean air cooler.
   4. Ambient temperature too high. Re-adjust engine room ventilation.
2. Boost air pressure too low
   1. Clogging of turbocharger filter.
      Clean or replace the filter.
   2. Clogging of boost air cooler air side.
      Clean air cooler.
   3. Fouling of turbocharger or its damage.
      Inspect turbocharger for cleanliness, bearing, blades and nozzle ring condition.
3. Bad fuel
   Change over to fuel from the different supplier if available.
4. Overload
   Reduce engine load