[Dieselwrencher]

I can't remember, was there any particular reason you went with electric fans over a mechanical with a clutch and a shroud? One way to test the air trapping issue in that hose would be this. Build a pipe out of steel with the ends and use a hose on either end to hook to the engine and radiator. Put a drain valve in the top of the highest point of the pipe. Crack the drain after filling it and see if air comes out. I know it wil be more work and a pain now that the truck is driving. I've had air get trapped in some builds and it can be a pain actually figuring out why it was there and why it wouldn't work it's way out.