ACDelco E.O.S. (Engine Oil Supplement) Assembly Lubricant is specially formulated as an engine assembly lubricant that helps provide protection against run-in wear and piston scuffing. It also assists in protecting against run-in camshaft lobe and lifter scuffing resulting from insufficient lubrication. This product is not recommended for use as an additive to engine oil. For professional use only. Not for retail sale.