I have a G5200. The cooling-system is barely adequate and must be maintained in top condition.
Certainly the fan shroud should be inplace. Also, the grass-catcher infront of the radiator needs to be removed and cleaned every couple hours of use. Only remove it when engine is NOT running... lest crud can be sucked into the radiator. I also use gentle blasts of compressed-air to keep the radiator clean.
One thing that helped reduce my G5200 temperatures was to do a cooling-system cleansing. I used prestone cooling-system cleaner and followed with 4 fill-run-rinse sequence. Finally, I rinsed with DISTILLED water twice and filled with 50/50 mix of antifreeze. (always mix antifreeze with DISTILLED water... tapwater is not sufficient.)
I got a LOT of rusty colored water out of the cooling-system the first 2 rinses.
HINTS:
*) I used a leaf-blower into the radiator-cap while the two drains were open. This blows out more fluid than simply draining the system.
*) Make sure the battery is mounted as far as you can get it from the radiator. Otherwise, it can block air entering the radiator.
Since I did the full system cleansing, my engine temps has remained exactly at one-half on the meter.
I realize a past append suggested 70/30 mix and I agree that more water will improve cooling.... HOWEVER, I live in Vermont and my tractor may experience -20F during winter storage.... hence, I use 50/50 to prevent winter freezing.