I read a tear down report on a C12 engine used in an over the road truck that saw normal heavy duty service compared to our RVs. Cat bought the motor to look at wear tolerances at roughly 1.25 million miles using standard approved oil. Their conclusion was that the main bearings, rings, valve train stc. was still within tolerance and had several hundred thousand miles of life at the current wear rates before needing any work. My conclusion is good diesel approved oils like Rotella or Delo changed at rational intervals are just fine and given the wear rates with those oils we will never reach end of life of internal components. Save your money.
I think that only using Cat filters for oil and fuel is a far better choice than the rest of the market place. Cat put a lot of effort into fuel filter technology with very high capture rates at .5 miicrons. Their oil filters by design are highly efficient and have excellent seals and very heavy well designed metal interfaces.
If I had to guess what we could do to provide excellent life it would be, watch fluid levels, belts, idler pulleys (pull the belt and rotate them by hand to see if they have smooth rotation) hoses, watch for any leaks, clean air filters, don't idle too long, until oil is up to temp be easy on the throttle, and avoid starting the engine unnecessarily. We are far more likely to have something external break that does damage than anything internal. Last but not least drive them at least once a month for 20 miles or so if you are not traveling. Just my 2 cents....
Later Ed
