Replaced head on Kohler cv20 a month ago with new head gasket, nuts, and washers. Circumstances dictated that head be again removed and reattached. There is now a small oil leak that appears to be coming from head gasket area. Pulled valve cover and added silicone and it is dry there. Question is, does the head gasket have to be replaced every time head is removed, and is it even possible for oil from push rod area of block to get past a head gasket, good or bad ??