Is it time for a new radiator?

I had a LA 360 in a 79 Ramcharger. Truck was built for offroad. I put a Ford fan on. One of those old huge ones with the big curved blades. It pulled so much air you could feel the suction when standing infront of the truck.
It pulled so hard it literally pulled the shaft out of the pump a couple times before I figured that out.
So, be careful with putting larger fans on.
Which is why I went electric.

But yes, what he said. Get the rad checked. Could just be plugged.