Fan too close to radiator?
Maybe not in your world but every time I do it it works.
So do exactly what you want but don’t say it doesn’t work.
Go read a better book. Or better yet, go build a cooling system that will keep your engine at 160 in all weather and let me know.
Not gonna answer the question then huh? What exactly did you measure in your high school auto class? Because I can pretty much guarantee that what you "tested" doesn't prove what you said.
I am willing to bet that I have read better books, and I have done far more than just cherry picking things from books I don't have a background in- I have formally studied both thermodynamics and fluid dynamics at a level far beyond a basic radiator.
It's true, not every automotive cooling system uses a fan shroud and not every one
needs one. If spaced properly the fan can work adequately assuming the whole system has been well designed.
But that's not the same as saying it doesn't make a difference. Without a shroud, the fan will not pull air consistently across the entire radiator core in most systems because the fan is smaller in diameter than the surface area of the radiator. And either way, you're still losing efficiency because you're not directing the air coming off the ends of the fan blades. If the system is good enough the lost efficiency may not mean the car overheats, but again, that's not at all the same as saying it doesn't make a difference.
A fan that is properly spaced in a fan shroud will be more efficient than one that is not and certainly one that doesn't use a shroud at all. Given a particular system an incorrectly spaced fan in a shroud may not work better than not having one, but that depends on the particular case. I don't want to assume too much, but given you're referencing a basic high school auto class I'm guessing you just looked at coolant temperatures, not actual air flow and certainly not the thermodynamic efficiency of the system. So sure, maybe the particular car you tested maintained its temperature either way. But that doesn't prove the shroud doesn't make a difference, it just proves that the cooling system for that particular car was robust enough under the very basic conditions you tested not to have a noticeable difference with the basic equipment you used.