Looking at a 2002 explorer with a 140,000 miles on it that's loaded and in very good condition. Owner of the vehicle is selling it dirt cheap under $2000 as his mechanic has told him it has a broken valve spring and the heads have to be removed in order to repair the valve. Everything else on the vehicle is great. I have a friend who's a mechanic but he's out of the country on vacation and I can't get a hold of him. Does this sound like a good deal and how major of an engine repair is this? Engine is 4.8 liter V-8.