Dirt or grit in the air, oil
play more of a factor in the long term health
of a motor
than just the numerical hours. I know of more than 1 diesel that has gone over 15,000 hours and a few that did not see 2000 without an overhaul
. A good mechanic
can give you some insights, but a detailed engine maintenance
log might be an even better source of condition.
I do flight instructing for the fun of it, and airplane engines that are run hard, but run hard every
day will typically make it to TBO, but airplane engines that sit, though low time, rarely make it to TBO.