Abstract: A bypass valve provides an elongated valve body defining a bore and a longitudinal axis. A first pair of axially spaced ports are attached to the valve body and include a service inlet port and a service outlet port. In addition, a second pair of axially spaced ports are attached to the valve body and include a valve inlet port and a valve outlet port. The bypass valve also has an elongated spool with an axis of rotation coinciding with the longitudinal axis while positioned to rotate in the bore between a service position and a bypass position. As part of the spool, a first curved land defines an outlet passage from the valve inlet port to the service outlet port, and a second curved land axially spaced from the first curved land defines an inlet passage from the service inlet port to the valve outlet port.