Some new Chevy Corvettes equipped with the 6.7-liter V-8 may experience an oil leak, according to a GM-issued service bulletin.GM says the new LS6 engine may leak between the oil pan and oil-cooler adapter, and a running engine might elicit bubbling around the adapter. A fix has already been identified, with GM saying the limited number of affected engines just need two oil-pan high-pressure port seals from a certified technician.