Re: Winterizing: Prestone vs RV antifreeze
I always drain mine first, but I run a bit of RV antifreeze through just to take care of any small amounts of water laying in places I can't completely drain. For me, its cheap peace of mind. We used the same process when I worked at the marina, and I never replaced an engine we winterized. I did replace several that people though they did properly, but never one that was totally drained dry and left that way, and never one that was drained and filled with RV antifreeze.
I don't use the green stuff though. Our boat is winter stored very near the water. So close in fact, a large part of the yard floods at a high tide, and most of it floods at a moon high tide.