I have headers and a tune........dealer said nothing. Its a TSB not a warranty issue, should be no problem. They will more than likely have to unbolt the drivers side header to get better access. Its a cross threaded nipple that occurred on some vehicles during assembly.....after time it develops a small coolant leak. There are lots of threads on this issue....check em out.
2010 Inferno Orange 2SS/RS M6 Black Leather,Sun Roof, OBX Headers, Haltech CAI , non synthetic fluids, Mike Norris tuned 419/413
Avenging Orange: 38 years of not buying into the Hype........and damn proud of it!!