The CleanFleet project was a 24-month demonstration of five alternative motor fuels and a control gasoline in 111 FedEx delivery vans. Delivery vans from Chevrolet, Dodge, and Ford were operated on compressed natural gas (CNG), M-85 (methanol containing 15 percent RFG), propane gas, and California Phase 2 reformulated gasoline (RFG). Control vans for each fleet were operated on gasoline. Electric vans on loan from Southern California Edison were also used by FedEx. Data were gathered on vehicle emissions, fleet operations, and facility and vehicle capital and operating costs.This paper focusses on vehicle reliability and maintenance. Maintenance experience is described, vehicle utilization is discussed, the results of oil analysis are presented, and future engine teardown and inspection plans are described.