Engine Room Discussions

[Wauk7042]

I have a 3306B Caterpillar genset that is over heating under load(Aprox 130KW). The S/N is 85Z05539. I have had the radiator cleaned, the coolant hoses are new, the suction hose is not collapsing. The water pump is new(Outlet pressure @1800RPM is 13psi) the thermostat is new(170F). Under load the coolant temperature is 200F and rising, as soon as the load is shed the coolant temperature drops to 175-180F). I Have checked the intercooler and oil cooler for obstructions, they looked good. I have verified the fuel pump timing, performed a valve set(There were no tight valves). One thing that concerns me is when the unit is under load the coolant temps is high as mentioned earlier, but the oil temp and intake air temperatures are high as well (oil temp aprox 195F, air temp downstream of intercooler is 180F). I did notice that there has been aprox twenty feet of exhaust pipe added upstream of the muffler, possibly causing excessive back pressure which would explain the engine cooling down once the load is shed.(Spec for Max. backpressure is 25"H20) I will need to check this. Wondering if anyone else has any ideas?

Thanks

[GLEngineer1956]

Did you try running the engine with the radiator cap loose to see if that solves the problem? It may be possible you have a high pressure air leak into the cooling system from one of the combustion chambers. I would check for a leaking head gasket, pre-combustion chamber gasket, a cracked cylinder head or a crack in the water cooled exhaust if fitted.

If there is an issue with the cooling system the oil temperature will also rise because the cooling water also cools the oil.

I also think that the stack length is a bit of a red herring because if it were a problem there would have been issues since the initial installation and there would be issues with the turbocharger boost