回複：回複：有兩個問題。。。。。

No engine oil should go through the intake manifold.  Therefore, intake manifold gasket 老化的話不會造成漏機油。Fuel injector 上老化的像皮圈不應造成漏機油。If you only saw intake manifold下麵是機油, I guess it came from a leaking head gasket assuming your new valve cover seal replacement excluded the possibility of a leak from there.