Abstract: A serviceable valve is provided for controlling the recirculation of exhaust gases within an internal combustion engine. The valve includes a housing having a first section provided with an interior chamber and a second section secured to and subtending said first section. A diaphragm is affixed to and interposed the housing sections and is in communication with the chamber. In response to a predetermined chamber pressure, the diaphragm is distorted in one direction from a predetermined rest position. The housing is mounted on a fitting, which subtend the housing second section, whereby said housing and the diaphragm are rotatable as a unit about an axis of the fitting to selected positions of adjustment. The fitting is removably mounted on the engine. Carried on the diaphragm is a stem assembly which is movable longitudinally in response to the distortion of the diaphragm. A portion of the stem assembly extends through and protrudes from the fitting and has a valve piece mounted thereon.