When hot, - Shoot the temps of the upper and lower rad fittings, not hoses.
You need 30* min, 50* or better drop in temp from top/bottom.
If there's little drop, - Shoot temps across rad, half way down.
Cool areas are plugged tubes, not flowing coolant, the bigger the cool area, the bigger the problem.
Before temp guns, I'd drag my knuckles across the front of the rad to find cools spots.
Good luck .
