Self-adjusting hydraulic valve tappet

A self-adjusting hydraulic valve tappet arranged in a guide bore of a cylinder head of an internal combustion engine and comprising a cup-shaped housing (1) formed by a hollow cylindrical wall (2) closed at one end by an end member (3) against the outside of which a cam abuts, a radial flange (4) provided in the bore of the hollow cylindrical wall (2) at a distance from the end member and guides for longitudinal movement of the hydraulic play compensating element (6) in a bore (5) concentric to the hollow cylindrical wall (2) and formed as a separate unit inserted in liquid-tight manner in the bore of the hollow cylindrical wall (2) and fixed therein, characterized in that the radial flange (4) is made of a material which has a higher thermal expansion coefficient than steel and the wall thickness of the hollow cylindrical wall (2) is thin walled at least in the longitudinal area in which the outer surface of the radial flange (4) is arranged so that during heat expansion, the radial flange (4) is capable of elastically widening the wall (2) outwardly.