Hi flow electric fan
Though less than ideal, I’m forced to run a pusher. SPAL fans are known for actually moving their advertised cfm.
For me, a 16” (30102047) has worked. Had to modify the hood latch/grille brace for fitment. Not quiet though.
A1 Electric Online Catalog -- Spal Cooling Fans and Accessories
Unless there are some other issues going on it shouldn’t be too tough to cool that S6 with the aluminum rad. Control the air flow. Close any big gaps between the rad and core support (with seals) so air is forced through the core - not allowed to leak around it.