I have a 1998 290 sundancer with twin 5.0 efi. It is stored in new jersey outside under shrinkwrap. I will be winterizing it soon but plan over the winter to install new manifolds and risers to both motors. Not over heating but boat is new to me this year and not sure when they were done last. After i do my install do i have to add anything to them? Not gonna run motors till spring but was just wondering that after i take old off am i going to loose all the antifreez.