The HO Cummins: Does it really need more frequent service?

[DieselWright]

I’m running the HO version with the Aisin transmission. I see guys with the standard output (SO) trucks pushing their oil changes to 10k-15k miles. Should HO owners be more conservative, or is the engine internals stout enough that it doesn't matter?

 

[RigSmith]

The HO injectors run higher pressures, and you get more fuel dilution than the SO version. I'd never push HO oil past 7500 miles, especially if you tow heavy.

 

[TorqueKing]

The HO engine is demanding on the cooling system. Keep your intercooler and radiator clean; it’s vital for maintaining low EGTs under high torque.