Couple things, temp guage or sender out of range.would need
a non contact thermometer to verify.
When flushing rad,was there any buildup in cores?
i just had a head gasket fail on a small machine, inside of rad was
slimy, used simple green to flush. Was spotless after.
A faulty rad cap that wont hold pressure will allow lower rad hose to collapse. Reducing flow.
Thats all i got for now.