Abstract: A hydraulic lash adjuster for use in internal combustion engines has a cylindrical body with an internal chamber and a hollow plunger cap which is reciprocal within the body. One end of the plunger cap extends outwardly from the body and there is a fluid passage extending through the plunger cap end to communicate with the hollow interior of the plunger cap. There are fluid pressure feed openings in side walls of the body and plunger cap to supply fluid to the hollow interior of the plunger cap. There is a spring urging the plunger cap outwardly from the body. The plunger cap hollow interior has a generally conical metering valve seat at the internal termination of the plunger cap end fluid passage. There is a metering valve positioned within the plunger cap hollow interior and with a generally semi-spherical metering surface formed and adapted to seat against the metering valve seat.