How cold before you winterize? (add antifreeze)

smokeonthewater

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a liquid expanding is not a problem nor is a slush since they would simply overflow... the problem is when water freezes to a solid block and THEN expands.
 

Scott Danforth

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Air doesnt freeze (at least above -461 degrees, it doesnt). yes, AF will freeze, and it will expand while freezing. depending on the concentration of AF and its dilution with water, anywhere from -86F to +32F
 

jayhanig

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Air doesnt freeze (at least above -461 degrees, it doesnt). yes, AF will freeze, and it will expand while freezing. depending on the concentration of AF and its dilution with water, anywhere from -86F to +32F

I cannot count the number of times I've read "air doesn't freeze" and I accept the premise. Those of us who live next to the ocean watch our heat pumps, door hardware, etc., deteriorate from salt air. The best way I know to prevent rust is to keep oxygen away metal. Most divers have experienced finding some metallic object on the bottom which survived for decades in the ocean, only to flake away to nothing only a short time after being recovered from the dive site. If you need a specific example, think of the CSS Hunley recovered off Charleston, SC. They couldn't let it just dry out; it would have collapsed upon itself.

It is with that in mind that I question the wisdom of just leaving internal engine cooling channels exposed to salt air. It seems to me that most of the "air doesn't freeze" advocates live inland, where rust isn't near the problem.
 

Scott Danforth

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Jay, many of us that live in saltwater have a heat exchanger on the motor keeping the insides filled with a 50/50 mix of EG and water. In colder climates (where the temp can get below -34) I would advocate a mix of 70/30. However I still pull the plugs on the manifolds in winter months (and I live in Florida).

Those of us that do not have a HX, will eventually have to replace the motor from corrosion, however whether or not you put anti-freeze in the block, the corrosion damage starts rather quickly (within a few hours of exposure to salt), and the EG or PG can not protect the metal (or even reach it) once scaling starts to occur.

Rust never sleeps
 

UncleWillie

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...But I have recently heard that a guy in Nashville said that it is safe to wait to winterize your motor until you see temps in the teens for a couple days (as long as the cold temps last only a few days and it warns up to above freezing during the day time)...

Here is a specific example of what happens inside of an engine block over the course of 4 days.
The block probe was placed down the Oil fill cap and was resting on top of the head and valve rocker arms.

BlockTempPlot.jpg

The air temp bottomed out right at the crack of dawn and the Block Bottomed out about 3 hours later at 10:30- 11am
A close look at the Raw data shows that the Block Temp bottomed out within 8 degrees of the air temp and and lagged about 3 hours behind.

Note that the Daytime High temperatures exceeded 50F every day.
If the temperature had gone below 22F, The block would have gone below 30F every night.
The block can easily freeze in just one night if it gets cold enough.

In this example, it is a 4.3L V6 block, inside of a modern well sealed Fiberglass Engine Box, under a 2" Sun Pad, Under a Bow to Stern Cover and parked directly next to the side of the house. This makes it about as well insulated as you could reasonably expect.
Your block may not cool off as quickly, but I wouldn't count on it.
One night below 30 degrees is risky if it wasn't warm and sunny the day before.
 

thumpar

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I have yet to read or hear of a block that rusted through by just draining. I have read of blocks cracked using AF because they did it wrong.
 

UncleWillie

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I cannot count the number of times I've read "air doesn't freeze" and I accept the premise. ... It is with that in mind that I question the wisdom of just leaving internal engine cooling channels exposed to salt air. It seems to me that most of the "air doesn't freeze" advocates live inland, where rust isn't near the problem.

The internal surfaces of the engine faced much worse damage from the direct exposure to the salt water during one summer than they will ever see in a century of exposure to "Salt Air" during the winter. The insides of an engine block do not have any way of ventilating themselves.
Air may make it into the exhaust pipe, but the way out is blocked by one or more water pumps.
It is more like a mine without any ventilation, not a tunnel.
Once the available oxygen in the trapped air volume had producing a few grams of rust, the process would be depleted.

If you are really worried about it. Drain the Block, Flush it with Antifreeze, and then drain it again.
The remaining Propylene Glycol (an Oil!) coating the internal surfaces, is the Anti-corrosion agent alluded to on the bottle.
Propylene Glycol is BioDegradable, and will continue to consume any ambient Oxygen within the Block.

We are way over-thinking the dangers of having a drained block compared to having a frozen one.
 

tpenfield

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Here is a specific example of what happens inside of an engine block over the course of 4 days.
The block probe was placed down the Oil fill cap and was resting on top of the head and valve rocker arms.



The air temp bottomed out right at the crack of dawn and the Block Bottomed out about 3 hours later at 10:30- 11am
A close look at the Raw data shows that the Block Temp bottomed out within 8 degrees of the air temp and and lagged about 3 hours behind.

Note that the Daytime High temperatures exceeded 50F every day.
If the temperature had gone below 22F, The block would have gone below 30F every night.
The block can easily freeze in just one night if it gets cold enough.

In this example, it is a 4.3L V6 block, inside of a modern well sealed Fiberglass Engine Box, under a 2" Sun Pad, Under a Bow to Stern Cover and parked directly next to the side of the house. This makes it about as well insulated as you could reasonably expect.
Your block may not cool off as quickly, but I wouldn't count on it.
One night below 30 degrees is risky if it wasn't warm and sunny the day before.

Excellent graph. Judging from the information, it looks like about 8 hours at 25 degrees (or less) would get the block to below freezing
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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and a wise oracle once said as little as 4 hours at 26 degrees would crack a block.
 

Deeper

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I have been told it doesn't expand like ordinary liquids do when it freezes. True? False? I don't know. I would like to know though.

Water is the only substance that expands as it freezes. Anything else will contract as it cools. Notice in the video, with the pure antifreeze bottle, the sides are sucked in, showing that it contracted.
 
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