<div class="htmlview paragraph">Engine durability refers to the ability of an engine to function properly and reliably over an extended period of time. Engine durability is a major remaining technical hurdle prior to expanding the use of methanol fuel. This paper will present engine durability data derived from the California Energy Commission's continuing Alcohol Fleet Test Program, review this data in relationship to previously reported engine durability information, discuss some of the possible reasons for observed effects, and suggest design considerations for further improvement in methanol engine durability.</div>