Quote Originally Posted by MpG View Post
Maybe this is the reason for the gap inside the TC rads?

Now that I think about it some more, any physical deformation that interferes with low-speed fan cooling, should only be magnified with the high-speed fans. Which doesn't seem to be happening.
It wouldn't be magnified with high speed fans because the supposed deformation is caused by the water and not the fans. The tubes expanding would create a smaller space for air, which makes the radiator more restrictive for air passing through. Therefore it is less efficient on lower rpm fans while the higher rpm fans can power through it (like a thicker vs thinner rad or a high fpi vs low fpi).