Plastic for cooling sucks.
Ive had 3 plastic radiators expire, thats all I can describe them as doing as when I pulled them, the plastic was so thin in spots that I coiuld break through with finger pressure and it gets very brittle. Cracks everywhere, one Minivan rad had clips molded into the tanks that the AC condenser clipped onto as well as the PS cooling line, I actually broke one of the clips while placing the condenser into that clip and it took out the whole tank. And it wasnt that hard to break the other when I took it out to replace it. Its just planned obsolescence. Found a 26" rad out of a 70s Jeep Cherokee Chief with 380K miles. No leaks, no corrosion. Try that with plastic in 45 years, as well as all the plastic harness connectors in these modern cars.