Not to sound silly but are the fans moving the air in the correct direction? Had that happen to a clients car once - wired wrong from factory. Pushing air thru radiator not pulling.
When moving down the road the fans are not even doing anything but going along for the ride. They are only for airflow while stopped or moving slow.
I reread your 1st statement a few times and realize it can be taken a few diffrent ways. ("roadtested")
Keep us informed.
Joe
