My mechanic over at Landmark Lincoln says I have oil down in the spark plug wells and that it will cost about $700 to fix it. He says he will reseal something, (don't know), but I was wondering how big of a job this is really? How many of you have done this? I have a 2004 LS V8 and I know this has been a problem with the car. I was thinking that maybe I can get a buddy (who's a mechanic) and we could do this. If it's just replacing valve cover and other gaskets, then why not? Also, at this time I will replace all 8 plugs, coils, EGR valve, oxygen sensors and mass air flow sensor. Possibility the two camshaft position sensors and crankshaft position sensor. Your thought?