Well then its doubtful its the FF Then. Someone probably did a drain and fill and used concentrate. Possibly they just replaced a bad overflow tank and filled it with concentrate.
1999 Ford Taurus 145k (Vulcan v6) - Mobil 1 High Mileage 5w30 | FL400S
2002 Buick Century 102k - PU 5w30 / Fram Ultra XG 3980 / Filter mag