The world of diesels is not like the gas engines. Many big diesels go a million miles. Usually about 5-6 hundred miles the engine gets what is known as a in frame overhaul. The bus owners rarely go 15 thousand miles a year. to go 100K miles takes a long time. So the engines last a long time. I have just traveled on 2 trips and traveled about 4K miles. A while ago I drove to Arizona to look at a bus Idid not buy. I did the same trip to Wa state at the beginning of the year for another bus I did not buy. Going to see a bus is fun. Having a bus with some RV stuff is great. I'm planning a trip tp the East coast, just to see the autum leaves change color. Crown buses are different from all the other buses. Wanna buy a GMC ? I got 3. Frank