More inspection = the radiator is clearly tilted inward at the bottom.
Measure from the back edge of the wing to the back edge of the radiator and it's 1/2 " at the top and 1.25" at the bottom.
It's difficult to measure the fan clearance but distances are close to the reverse, that is, <1/2" at the bottom and >1.25 at the top. And that's with smashed fins at the bottom.
Shouldn't the fan and radiator be parallel at every point?
I'm wondering how much flex there is in the fan at speed. In the garage rpm is low whereas at 55 mph there might be enough flex to produce contact.
eh?
Thank you for helping me think this through. I need a new radiator, but if that's not the problem I'll eventually be buying a third!
