You need to use a polyurethane chalking. The factory stuff is made by sika i think. I couldnt find this and used DAP polyurethane chalking from rona and it worked amazingly well. We tried all sorts of expensive sealants at my last shop without much luck but this DAP stuff is working perfectly with coolant. Cant reccomend it enough:
https://www.rona.ca/en/slate-gray-po...00-ml-04915136. Clean it up good and degrease it with solvent like brake cleaner before applying.
Not sure what to tell you with paint. I painted my enclosure with typical oil rust paint and used another brand oil rust paint for coolant tank and neither is doing all that great. Paint has peeled off where it was bare metal, stuck where it was painted but its kinda soft, chips kinda dig into it while cleaning. If anybody has any suggestions of good paint please post.
Ways dont look the best, sand it down, then stone it to be sure you got all high spots then sand it with very fine sandpaper. Youll never get it back like factory but will probably work just fine. Just be sure to get the high spots taken down, and then smooth it with fine sandpaper. Dont use coarse emerypaper. Id probably start with 320, will take longer but avoid putting deep scratches in it. I wouldnt move the machine AT ALL until you clean that rust. That will be very hard on the turcite or rip it off like that.