working on a Volvo L70e wheel loader. Temp gauge gets up to the red area and sounds the alarm for high engine coolant temp. No obvious issues...coolant is full, belt is okay, radiator is clean. A temp gun indicates between 200 and 210 degrees on the engine. Radiator fan doesn't seem to be speeding up for extra cooling. I'm thinking a sending unit?
We had an L90 that would do that when the alternator got bad. That thing would eat alternators. You would get the false heating issue, and shortly after the battery warning.
What happens if you unhook the temp sensor? Does the fan go to max speed?
Is the cooling fan turning, are your brakes getting charged?