Originally Posted by pouncer
I'm looking at a bus that has just over 11k on the hour meter and 145000 miles. Do the high hours sound right with the miles? The bus is in Michigan so it may have idled a lot.
The hours sound way too high for the miles. Either the bus has more miles, or it spent many hours idling each day.
Most diesel engines have a B50 rating ... the miles that 50% of them can go before needing a rebuild. That figure roughly varies between 400 and 500k miles, and roughly equates to 12/13000 hours running.
School buses use is considered "severe duty" so the numbers usually come down a bit, and an engine that has 11k hours could be very close to needing a rebuild.
Have a mechanic with the correct tools test it before handing over money.