The description of the symptoms and the pictures of inside the radiator are pretty indicative of a stopped up radiator. If it were me, I’m going to assume the rest of the cooling system doesn’t look pristine. I’m pulling the thermostat housing and replacing the thermostat, and flushing out everything else I can with a garden hose. Maybe even add a coolant filter to catch any of that, that may still be circulating through. I’d even be considering replacing the water pump if it is of unknown age or condition.
Sent from my iPhone using Tapatalk