Motor Life

the accrued operating time of any machine with an internal-combustion engine (such as an automobile or tractor), or of an internal-combustion engine itself, up to the limiting state, when further operation is impossible or involves an unacceptable reduction in efficiency and violations of safety requirements. For transportation vehicles, motor life is defined as the distance in kilometers traversed from the beginning of service until the limiting state is reached. For tractors and other non-transportation vehicles, and also for internal-combustion engines, motor life is defined in terms of the number of hours of operation; for agricultural combines it is given in terms of the number of hectares harvested.