Yeah, I tried that one. The closest fit for the clutch nut was a 36 mm wrench end, but it’s not a perfectly tight fit and the wrenches are, by design, so narrow that they don’t provide enough grabbing surface to avoid rounding the nut castellations. I’ve been spraying the nut with PB Blaster a few times a week and lightly tapping on the sides of it with a hammer, in the hopes that eventually, it may break up enough of the rust for me to get it off without having to remove the water pump.
To that end, I bought this wrench to use on the nut:
https://www.lowes.com/pd/Kobalt-Chrome-Vanadium-Steel-Adjustable-Wrench/50029432
I like the fact that the design of the handle allows one to slip a pipe onto it for extra leverage. BUT, it was expensive and I don’t know if there’s enough clearance for it to fit on the nut, so I’m keeping it in the original packaging in case I have to return it. The fan shroud is history and the fan blade is pretty busted up (which is why I bought new ones in the first place). I might be able to gain some more room in there by cutting some of the fan blades with my reciprocating saw, but then if the nut still doesn’t come off, I’m kind of boned. Decisions, decisions...