I was driving recently and randomly it came up with a warning and said Engine hot - I genuinely have no idea, I've only done journeys recently in it from 10-20 Miles and its seems fine - it appears the viscous fan maybe stuck on all the time
Any ideas?
2011 4.4 tdv8

If the fan was on all the time it should never overheat. It may have failed full stop.
On a run the air passing through the rad will be enough to fight the engine heat, it's when you come to slow up and stop the fan takes over.