Mystery solved!
Rather than speculating I went for a test drive, noted it was doing the same thing - temp climbing even while cruising at 55 - 60.
Came back home, got on my back with a flashlight. It turns out that a plastic flap that is hung at the top of the radiator has to come down, tuck over the bottom of the front bumper and this is held in place w/ a plastic tab. It seems this piece has come loose and at speed this piece is piece is pushed back to the radiator. With both fans running, this piece get sucked towards the radiator further worsening the problem.
Hah! I don't have to spend a whole day wrestling with a radiator!
