Check coolant level, then lift the front end of the sled up high, remove coolant cap, start engine and warm up, this should help remove air in the coolant system. To help cooling engine, also consider add scratchers, see Holz Racing Products || ATV - 450R || UTV - RZR RZR-S || Sled - Rev IQ RMK
. I will get a pair of these myself.
Since the light comes on after 5 mins it makes me think there is something more serious stuff going on, like water pump failure, but I guess since your heat exchangers are hot, this is probably not the case.