While replacing the EGR this AM I managed to dislodge the flared fitting from the nut at the exhaust manifold. Heck, I never felt any sense of resistance while connecting at the EGR end. Never noticed it until I started it up. Anyway, the nut on the manifold looks pretty corroded and seems to be doped with some kind of compound that is pretty well dried. I'm pretty much afraid that if I try wrenching on that nut it's going to ruin the manifold - am I right?? Is there a good way to do this or do I need a 'real' mechanic with a torch to heat up the nut?

TIA,
Chiz