Cliff..If you past 5yr. warr. its not covered. AFAIK.. it should be w/$100. ded.JMO! Tec. cleans t. or it gets a reman.t. Look at TSB 06-4-12
6.0 PowerStroke bulletins
What was said about coolant leak, exhaust smell in cab etc. Look at TSB list. If your ok with dealer/svc then possibly a misunderstanding..talk with svc. mgr. If still no go..ask to have a fmc field rep involved. Stand your ground, but have patience, unless you have other dealers near by.
Good luck!