Winterize- Add Antifreeze then drain?

[boatdude100]

mercruiser 3L 1995, alpha one - Winterizing Hybrid procedure?

Please correct me if this sounds like a bad method:

1. Run to what is hopefully operating temp on Muffs with water
2. Remove thermostat (to make sure antifreeze circulates in case it was not at operating temp)
3. Drain Block - 2 plugs (to make sure antifreeze is not diluted) Replace drain plugs,
Fill Block with antifreeze thru thermostat hose
4. Restart boat with antifreeze running thru muffs and use 5 gallons? of antifreeze
5. Drain engine once again

Much much appreciated...

 

[Lou C]

Ok just remember this and this is stated in Mercruiser manuals:
You drain water to prevent freeze damage
​You add antifreeze to reduce corrosion damage in the off season, and for that to work, it must be the AF with corrosion inhibitors not the RV kind

​So, I run the engine till warm, change oil. Then run it again after checking the oil and filter and then fog it. Then manually drain all the water, poke the holes in the block and manifolds because they can get blocked by rust. Disconnect bottom of big hose from therm housing to circ pump let it drain. Disconnect raw water intake hose from transom mount at the therm housing (Alpha and Cobra) or impeller housing (Volvo and Bravo) and point it down to drain. Then take a funnel, put it in the hose hold it up and fill with AF till it runs out the water intakes on the drive. Replace drain plugs, if metal put some gasket sealer (OMC gasket sealer, Merc Perfect seal, Permatex Aviation) on the threads, will come out easy next time. Then reconnect bottom end of big hose at circ pump. Disconnect top end and put a funnel in it. Fill engine with AF till it runs out neck of therm housing. Engine is now full of AF no need to remove thermostat. Next, disconnect manifold feed hoses at therm housing. Fill them with AF till it runs out exhaust (Note, this is why you use marine af you must not use the toxic auto ethelyene glycol af!)
​Now some engines have other components that need to be drained, you really should check the shop manual for that. This is just a basic guide of the safe way to use AF. And its in Merc's shop manual for all the nay sayers.

​And remember, you add AF ONLY TO REDUCE CORROSION DAMAGE, if you drain it out, you're wasting your money! Once its drained, PROPERLY it will not freeze.

 

[Scott Danforth]

The manual also states to add AF via a funnel to the thermostat housing. It does not say use muffs

 

[tpenfield]

That procedure should be fine. The exhaust manifold will initially have water in it, since you did not mention draining/filling it., but if you fill the block with AF and also run 5 gallons of AF into and through the engine, it should be enough AF to purge the water from the exhaust manifold.

 

[stonyloam]

BAD! Just drain it.