My 235 seems to cruddy up its coolant after a flush…way too fast. This is all in spite of several flush “hacks” I’ve tried here. Muriatic acid, blasts of compressed air through block drain, etc. I get crystal clear water draining, and within a few months it’s gross again. I also suspect the modern formulation of traditional green coolant has been neutered by regulation.
Would one of the big spin on coolant filters like used on diesel engines be of any use? I wouldn’t see this as a permanent measure. Just thinking given some time all the crap in the bottom of water jackets would find its way into suspension and into the filter.
But that’s all just theory with no practical experience with coolant filters.