Exhaust housing symptoms

[ttles714]

Are there any visible symptoms to exhaust housing failure on an F250 (2007) ? ( other than dropping the lower unit and looking inside.)

[Crazydays]

My 225 hp after running back from a trip and coming in to dock would alarm at the con*****er. I had no temp gauge. Did this consistently and when I pulled the lower unit and looked up it was corroded severely.