I have a friend who has a bad oil leak on his 2006 5.3 GMC Sierra with over 300,000 miles. I crawled under it to take a look and after wiping off the bottom of the engine I could see a steady drip coming off of the starter when the engine was running. The starter is mounted about halfway up the bellhousing on the passenger side. The only place I can think of that would cause a leak above the starter is the valve cover on that side. I checked the bolts on the valve cover and they were all tight. Does anyone have any experience with a similar leak? If it is the valve cover gasket, do you have to remove the intake manifold on a LS engine to change the gasket?