An exhaust after-treatment system including an exhaust passage having at least a first portion and a second portion. An exhaust treatment component may be positioned within the exhaust passage between the first and second portions, and an insulating blanket insulates each of the first portion, second portion, and the exhaust treatment component. Temperature sensors may be positioned at the first portion, the second portion, the exhaust treatment component, wherein each sensor monitors the temperature at its location. A controller may have access to temperature data associated with an insulated exhaust after-treatment system, and the controller compares the monitored temperatures to the temperature data to determine whether a difference exceeding a predetermined threshold exists. If the difference exceeds a predetermined threshold, the controller outputs an error signal identifying particular portions of the exhaust system that are no longer insulated.