I had a strange smell of burnt oil one day while driving my s90 i could not see any obvious reasons for it until i took off the cover to the spark plugs and noticed oil i cleaned the area and took a drive and it appears as though oil is coming up through three bolts that hold down the valve cover. Eventually enough builds up then gets onto the exhaust manifold, my heat stove is removed mech did not like it there any suggestions would be greatly appreciated thanks peter