International 4700 help.

[white93]

What temperature does the high coolant temp alarm go off at? It has a 7.3 and an allison in it. Its my friends company tank truck and it fell victim to a bad gauge cluster. The gauge red lines a little bit before 280 so I'm thinking maybe 250-260? Its broken and he said never worked. He told me the driver ran it until it went from a steady beep/flashing til it started some kind of morse code and de-rated the engine. He was asking me but I have no idea. It usually grosses around 35k so its just working too hard I guess.