I am looking for info/recommendations on the cummins 5.9l diesel engine. Specifically the HO vs SO. Was there a problem with the SO in the past? If not, why is Dodge now going to all HO's in their new trucks, when a diesel is specified? Does the SO have a cast iron cylinder head? Any pros or cons between the two?

 

Only differenct in the HO and the SO (2nd gen anyway) was slightly different injection pump, programming, and very minor engine differences.

The engine is, was, and always will be the basic 5.9 Cummins ISB.

Everything's going HO these days due to marketing.
People want Heavy Duty, High Output, more bang (they think) for their buck.


phox

 

The HO has smaller injectors @ higher pressure and higher compresion ratio. The HO has 10 more ponies and 50? fottpounds on the SO. The HO was equipped with the 6 speed in manual configuration while SO had 5 speed (with the advent of the HO in 2001).

The HO before common rail wasn't available in California due to CalEPA regs. I can't think of a good reason to prefer the SO...hence the conversion to all HO's. That's what the people want. Sex....errrr..I mean power, sells

 

I think that they are making the HO the basic package now because of the 600. These are the new HO
dave