Double checking winterizing Merc 5.7 Bluewater v-drives....

[YeOldeStonecat]

Searched pretty far back in this forum and YouTube, I see lots of info on raw water cooled engines, with I/O's....but not so much on the half closed systems like I believe mine is. This winter I'm tackling it myself, always had the yard do it in prior years, but they doubled in cost this year...so..ouch, tackle myself.

See below pic, I'm pretty sure I have engines that only have coolant from the heat exchanger go through them. Taking drain plugs out, yellow coolant pours out, no clear water. I don't "think" anything else on the engines takes fresh/raw water through it...correct me if I'm wrong.

But my manifolds, risers, elbows...the blue drain valves on the bottom release clear water.

So my winterizing steps....while she's still in the slip...is this a complete list? Tips?
*Pour gas treatment in both gas tanks, run engines for a bit, let cool a bit.
*Already changed engine oil and filters in both a couple of weeks ago
*Close seacocks for raw water intake...
*Drain manifolds via the blue plastic thumb screw valve on the bottom...
*Drain raw water pumps...find whatever connection is lowest....
*Drain heat exchanger by pulling one of the hoses that I think may be the intake from water pump. Perhaps aid in sucking out more by trying to connect a wet vac hose?

**If I recall, some water lines run forward to the transmission oil cooler. Ensure those get drained...perhaps assist with shop vac from one end?

Or does anyone recommend still trying to get antifreeze through the raw water system by opening up the strainer from the raw water intake...and pouring antifreeze into it til pink shoots our exhaust?

 

[mrsrobinson]

Once you drain all the raw water I do recommend you push some antifreeze through the raw water side.

 

[Bill Curtis]

My engine is set up like yours, except a Bravo3.

In addition to yours routine, I will:
Pull the small plug from bottom of oil / PS cooler(s) to drain the cooler(s).
Pull hoses off raw water pump. (I store on trailer)
Drain the heat exchanger and pull end caps to check for cleanliness / debris. The exchanger may or may not have a zinc anode in it (attached to the plug on the bottom). If it does, replace with a new one.
Pickle the engine by running fogging oil through the intake before final shut down. Keeps valve train and rings lubed during layup. (smoke keeps skeeters away)

This routine eliminates all the raw water and the need for running "pink stuff" through the system.

Still need the pink stuff for the fresh water systems in head, sinks etc.