It's very rare for a 240mm rad to encroach on ram, most 240mm are either offset away from the ram or there's enough space above the tips of the ports to cover the distance. It's generally the 280mm that run into issues as their width negates any offsets.
There's also placement to consider, not all motherboards have ram slots at exactly the same height on the board, just because of that, some place the slots slightly lower, so ram height becomes less of an issue as it's under the rad/fans anyway.
According to the web posts, with a 280mm Arctic, on a 4000D there's 39.17mm of ram clearance. The Neo's are 44mm tall. With a 240mm, shouldn't be an issue even centered you'd have 49mm of clearance.
Just make sure you install the ram first, and pc works, before finalizing the rad installation. Or you'll be pulling it all apart again.