A vane-type camshaft phaser includes a rotor having a plurality of vanes disposed in a stator having a plurality of lobes, the interspersion of vanes and lobes defining a plurality of alternating valve timing advance and valve timing retard chambers. Each vane and lobe tip is provided with an axially extending groove having an outward expansion of width. A wiper seal element, formed by stamping and folding from a single piece of sheet material, has folded wings that extend under compression into the groove. The spring loading of the wings against the tapered walls of the groove acts to urge the wiper seal element out of the groove and toward the opposing stator or rotor wall, thus ensuring a continuous forced sealing contact of the wiper seal element with the opposing wall and the groove walls during operation of the camshaft phaser.