Winterizing and antifreeze to use in Mercruiser 4.3

[Lou C]

As far as the volume of the block, heads and intake manifold, it took a bit over 2 gallons to fill my 4.3 V6 yesterday and I think a V8 would take at least 2.5 gallons. However the cooling passages are closed to the air when you replace the drain plugs and hook up the hoses. Each exhaust manifold holds about a gallon...

 

[QBhoy]

As far as the volume of the block, heads and intake manifold, it took a bit over 2 gallons to fill my 4.3 V6 yesterday and I think a V8 would take at least 2.5 gallons. However the cooling passages are closed to the air when you replace the drain plugs and hook up the hoses. Each exhaust manifold holds about a gallon...

Hi Lou. Agree with your volume numbers.
but if the block is empty of liquid...it is open to atmosphere through the hoses in fact. If you think about it, surely this is the case, by route of the hoses from t stat to exhausts. Then open right out through the exhaust and drive. Can’t think why it wouldn’t be.

 

[Lou C]

The point about the exhaust allowing air in and that can travel via the hoses to the tstat housing is a good one, but if the t stat is closed, not much air flow would take place I'd guess, depending on the design of the thermostat housing....
I'll keep filling mine up with AF, till I re-power and that engine will have closed cooling as they all should from the factory!

 

[QBhoy]

The point about the exhaust allowing air in and that can travel via the hoses to the tstat housing is a good one, but if the t stat is closed, not much air flow would take place I'd guess, depending on the design of the thermostat housing....
I'll keep filling mine up with AF, till I re-power and that engine will have closed cooling as they all should from the factory!

Thanks Lou. Yeah. There will always be a free transfer from atmosphere there. Even with the thermostat. For sure.
yeah. I fill with AF too. Just to try and reduce the oxygen levels a bit. Empty and damp over winter is where and when the corrosion happens. Nothing more certain. During the summer the engine and system stays mostly full of water, reducing the chances of corrosion. Not the case in winter, if it’s left with nothing in it. Literally perfect conditions for corrosion like this.

 

[alldodge]

Might need to rethink how fun oil threads are opcorn:

 

[QBhoy]

Might need to rethink how fun oil threads are opcorn:

Haha. Get your point AD...swore I’d never get involved in these kind of posts again. Can’t help it with this one though. It’s a real gripe of mine. Always amazed to hear the thinking that the block empty would somehow turn into a vacuum when the drain plugs are in. Often from otherwise clever guys too.
anyway. I’ll get over it.