"100 hrs is a rule of thumb ov
"100 hrs is a rule of thumb over the years but newer oils have additive packages that allow it to survive better than in past years. Also, it is good to consider a "time or engine hours which ever comes first" policy. In both cases you are exceding prudent measures. Keeping your oil changed is the key to longevity. With timely oil changes an engine can easily go 10,000 hrs or 30 years without a major overhaul. I trust that you are using a crankcase oil rated for use in diesel engines and verified the proper viscosity for your engine."