I regard the fan unit as what I call an electro viscous fan; I also had to replace mine or at least did replace mine.

The fan is what I call expensive, $632.00 just for the part, but it had sort of locked on, which is of course the desired failure mode.

Incidentally, per a previous post, I am now not convinced that the fan was the problem as the alternator later was also replaced.

At the time however, after replacement, the fan noise problem did go away.

And yes, upon startup on a cold morning, there is still routinely the roaring sound for a couple of minutes, then quiet. You get used to it.

Should I again have the fan noise problem, I will spend more time investigating the state of the alternator and electrical system before replacing the fan regardless of what the dealer LR computer codes indicate.