Antifreeze

[MAXUM]

Originally Posted by bobkatfly

So after running antifreeze through an I/O, do you leave whatever is left in the engine or do you pull the lower drain plugs and let it all drain out? I've heard that leaving it in affords some corrosion protection. The marina's that experienced the bogus A/F must routinely leave it in for them to be worried enough to redo the boats. In the past years I've let it all drain but this year I left the plugs in after running it through.

I've always left the engine full of antifreeze, then again when I winterize mine I don't run the A/F through the stern drive, instead I drain all the raw water out of the block and risers then backfull everything including the stern drive from the coolant hoses on the block from inside the boat. Yes some stuff advertises corrosion protection. Whether or not that protection is significant or not is hard to say but I prefer knowing that there is antifreeze in there versus not. Opinions vary on this in reality it probably doesn't make a difference either way, just as long as there is no raw water anywhere in the system that could freeze and create a problem.