Can sterndrive freeze and crack?

No Worries

Seaman
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Nov 6, 2016
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Hi guys, first time boat owner as of September. I'm confident I winterized the block and exhaust manifold by draining and filling with -60 anti-freeze. I pulled the hoses off either side of the thermostat housing to pour in a/f and fill her up. My only concern is the fact that I didn't use muffs to pump a/f through the intake on the sterndrive. It's a 1983 3.0 Merc with an alpha one. Thank you gentlemen for any input. Also, the gear lube in the lower unit is good and clean...no water.

-Come on summer!
 
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wrvond

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Mar 2, 2010
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My manual doesn't say anything about using muffs to pump anti freeze through the outdrive, so I'm not sure where this idea that it should be done comes from. On my 3.0, when I remove the two hoses and pour anti freeze into them, at some point it starts coming out of the out drive, which makes sense if you think about it. The water that cools your engine comes from the lower unit intake - you're just running the fluid backwards through the system using gravity.
​My MerCruiser manual also states the outdrive should be stored in the down position. If your boat is stored outdoors, you should cover the prop to prevent water from collecting there and freezing.
 

Scott Danforth

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No factory manual ever said suck up AF thru muffs.

As Fun Times stated make sure all the drain ports are clear, store outdrive down or leave off when you inspect the u-joints and bellows

You are pulling the outdrive to inspect the bellows and u-joints, correct?
 

savetexomabeaches

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I don't even put AF in my 3.0. I open up the two drain holes on the port side of the engine, poke them with a small wire to make sure they are clear, remove the hose up front. It lets all the water drain out. Lower the drive, drive self drains, remove prop, wrap in plastic.
 

No Worries

Seaman
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Nov 6, 2016
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No factory manual ever said suck up AF thru muffs.

As Fun Times stated make sure all the drain ports are clear, store outdrive down or leave off when you inspect the u-joints and bellows

You are pulling the outdrive to inspect the bellows and u-joints, correct?

Yes but I didn't intend on doing that until the spring. The exhaust bellows is shot and so I'm just going to replace all three Bellows while I'm in there. Again, I didn't intend to do that until the spring. I was just going to leave the drive in the down position and on the boat for the winter.
 
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No Worries

Seaman
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Nov 6, 2016
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you at least drained the gear case and refilled.

No, I cracked it open and the gear lube came out clean with no water. I see where you're coming from though. I think I'm just gonna pull it off and put in the basement for the winter. I appreciate your help, I'm very mechanically inclined, I've just never owned a boat and of course have no manual. Outside of water getting in the gearcase, is there any way water can be trapped in the water intake? I have little weep holes towards the front of the bullet...is that the raw water drain? Thank you.
 

achris

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May 19, 2004
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That 'weep hole' is a cavity drain. Make sure that's clear and the front drive cavity is fully drained.

Water could be trapped above the water pump impeller (it can't drain back passed the impeller, despite what a few 'shade-tree' mechanics think :facepalm:). That's part of the reason it's 'suggested' the drive is pulled and a full service is done on it. A full service includes checking the water pump impeller. That allows any water to drain from the water passages above the impeller.

Chris...
 

H20Rat

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Water could be trapped above the water pump impeller (it can't drain back passed the impeller, despite what a few 'shade-tree' mechanics think :facepalm:). That's part of the reason it's 'suggested' the drive is pulled and a full service is done on it. A full service includes checking the water pump impeller. That allows any water to drain from the water passages above the impeller.


Is there ever a recorded history of that ever happening? I've lived in the cold frozen north my entire life, and have owned boats now for 25 years of it. Never once have I used muffs with antifreeze, or pulled an outdrive. I've also used outboards in well below freezing weather, where I loaded it and immediately trailered it home, without doing any winterizing whatsoever.

I would suspect the impeller does a pretty crappy job at actually sealing, and there is more than enough room for water to fairly quickly leak out.
 

Bondo

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Ayuh,..... I'm a redneck shade-tree Mechanic myself, 'n the only frozen busted lower unit I've ever dealt with was left in the up position,.....

The torpedo weep hole froze, then more snow/ rain filled it up, which froze, 'n split the case,.....

In my personal experience, outboards, 'n sterndrives allow enough water to leak past the impeller when in the down position, that a solid freeze don't hurt a thing,...
 
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