There is no way to tell when your motor will fail. Many say you can go by mileage, so if the average failure rate on a Sprinter Transmission is 110,000 - 125,000 miles, then you either decide to replace the older vans as they reach 100,000 miles, and still have some resale value, or plan on buying a $4,000 transmission for them in a few months.
Motors give little warning that they are about to die. Anything from your Air Conditioner to the fuel pump can fail the next 10 hours that you run it, or last another 10 years.
It would be expensive to replace a fuel pump motor every 50,000 miles when the average life is closer to 100,000 miles.
I have always heard that if you keep the pump underfuel, it will run cooler and last longer. SO keep 1/4 tank or more in the RV, and the pump will run cooler.
Fred.
