回複：四缸

On a 4-cylinder engine, an intake manifold is mounted on the back side of the cylinder head.  There is no engine oil going through the intake manifold.  On the top of the cylinder head are the valve stems and a cam shaft covered with valve cover.  Check whether the oil comes from the top or the bottom of contact between the intake manifold and the cylinder head.  If it is noticed on the top, it is more likely from the valve cover leak or a cracked cover.  If it is only noticed on the bottom side, it could come from a leak from the head gasket.