Valve Lash Adjuster
WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The lash adjuster, or lost motion assembly (207), includes a spring and retainer. The lash adjuster is in constant contact with the mid (3) rocker arm. At low speeds, the lash adjuster suppresses unnecessary movement of the mid rocker arm. The lash adjuster functions as an auxiliary spring at high speeds to ensure smooth valve operation.