At what temp will an engine with water freeze?

[DriveHard]

Maybe this belongs in the boating section, but I was thinking it would apply to race cars, and anything where folks might not use anti-freeze.

Tonight is supposed to dip down to 28F...my boat is still sitting on the water (on a lift, out of the water, but under a cover). Obviously the water temp is still well above freezing...but with the boat sitting 2 foot off the top of the water, it makes me nervous. I was thinking of running down there and at least plugging in the battery charger which sits in the engine compartment, and would create heat along with the batteries.

So...what air temp would freeze and crack a block? Iron heads, Iron block in this case...

 

[SHOZ]

What's the wind like? If no wind I would chance it. But if it's windy it will quickly cool things down to air temp.

 

[emmett442]

The point where the water freezes solid and thoroughly is where you have to be concerned. A few hours of 28 degree air temp around otherwise warmer equipment will never get there. At worst, a little slushy content starting at the highest/most exposed points. But even that is unlikely.

 

[cjcride]

Should freeze at 32f or 0c.
The slush is most likely though if only a couple hours of 28f
Can you plug in a small heater?

 

[wavinwayne]

This past winter, one night it got down to 0°F here in North AL. I had some 1 liter bottles of water in the trunk of my car that didn't freeze. I wouldn't stress over it. If the boat were exposed to high wind at 28°F my opinion would be different.

 

[thastinger]

Maybe this belongs in the boating section, but I was thinking it would apply to race cars, and anything where folks might not use anti-freeze.

Tonight is supposed to dip down to 28F...my boat is still sitting on the water (on a lift, out of the water, but under a cover). Obviously the water temp is still well above freezing...but with the boat sitting 2 foot off the top of the water, it makes me nervous. I was thinking of running down there and at least plugging in the battery charger which sits in the engine compartment, and would create heat along with the batteries.

So...what air temp would freeze and crack a block? Iron heads, Iron block in this case...

Takes a lot of energy to freeze a block solid enough to crack it, if it is below freezing for just a few hours you'll be fine, if it is 28 for 48 straight hours then maybe you would have something to be worried about.

 

[Marcozi]

What's the wind like? If no wind I would chance it. But if it's windy it will quickly cool things down to air temp.

Wind speed is irrelevant. Inanimate objects sense only the actual temperature and not wind chill.

 

[eljefino]

I have an unheated cabin in the same predicament, a couple hours at 28 will do no harm. You have a lot of thermal mass in that engine.

I found a case of beer that spent an entire winter on an island in Maine in an interior unheated closet; it was just fine.

 

[SHOZ]

Wind speed is irrelevant. Inanimate objects sense only the actual temperature and not wind chill.

BS big time. Not talking about wind chill. Wind chill is the added cooling effect from evaporating water. Talking about heat going to cold and wind accelerating that. Air molecules carrying away the heat just like a furnace or AC and a blower.

 

[Urshurak776]

A few years ago in Charlotte, NC we got down to 11 degrees. Very rare down here. I had two cases of water in the trunk of my car, plus some soda, that I needed for a training class the next day. I had completely forgotten about how cold it was going to get that night. I woke up that morning, showered and dressed and when I went outside to go to work, it hit me.....

Popped the trunk and they were all fine. Ready to drink! Nice and cold! No freezing.

 

[D60]

Everyone go get rid of that +32 windshield washer fluid you've been carelessly running all summer!

 

[RedSpider]

Personally if I couldnt get to the various drains to get the water out of the block I'd lower the boat into the water. I may be a bit paranoid though, I watched my idiot brother in law spend 20 grand on a racing engine for his boat, then figured he had "a few weeks" to winterize it even after multiple sub-freezing days. He was still paying for that engine two years after he sold the now non-running boat.

I opened all the drains on mine after every outing even in the middle of summer. Didnt take care of anything left in the drive but at least the engine was safe if it got into late fall before I winterized it.

 

[oil pan 4]

Problem where I am is they can't call a low. They'll call for 28f and we'll get 24f.
Put a squirt of RV antifreeze in each side of the block.
Or install valves that drain all the water out of the lowest recess of the block.

 

[LenZee]

Wind speed is irrelevant. Inanimate objects sense only the actual temperature and not wind chill.

Inanimate objects can cool faster to ambient temperature due to wind. Just to ambient though. His engine shouldn't be directly exposed though unless it's an outboard. the lower unit water pump may freeze though if exposed.

 

[ecotourist]

Wind speed is irrelevant. Inanimate objects sense only the actual temperature and not wind chill.

What you say is true for a static situation (ie days of a similar temperature), but you're not considering the dynamic nature of cooling. The question is how fast will the block and water freeze with an overnight temperature of 28F. And for that question wind speed (wind chill) matters a lot.

For the OP you need to consider the consequences. It probably won't freeze if the overnight temperature hits 28 F. But what if it does? I'd at least warm that engine up before bed. and probably put an old blanket over it.

 

[burbguy82]

I was thinking of running down there and at least plugging in the battery charger which sits in the engine compartment, and would create heat along with the batteries.

This would be useless.

So...what air temp would freeze and crack a block? Iron heads, Iron block in this case...

Really you have to think of it not as the cold, but the absence of heat or rate of heat loss. I am not schooled enough to answer this question, maybe @MolaKule is? Would be a "cool" topic and or learning experience for sure.

This question is very common in plumbing when talking about freezing pipes. ......on why pipe insulation does not prevent freezing, it just slows it down.

Honest question though, on a practical level..........why not just plug it up when the temps get below questionable?

 

[SHOZ]

Everyone go get rid of that +32 windshield washer fluid you've been carelessly running all summer!

I worked for a company that had a fleet of trucks. Their headquarters was in Florida but the production was in Illinois. They always would fill the trucks washer tanks up with the +32F washer fluid and it was a mess. No way to thaw it out when it's below 0F. We use to give them a squirt bottle to use till they got down south. Of course then it thawed and no one thought about it again.

Same with the normal -20F washer fluid. If the windshield is cold and no heat for the defrost and temps below 0F, the alcohol will evaporate first leaving behind frozen blue water when moving down the road. I use the stuff with propylene glycol in it too for winter use here, generally sold as -30-40F washer fluid.

 

[ecotourist]

I opened all the drains on mine after every outing even in the middle of summer. Didnt take care of anything left in the drive but at least the engine was safe if it got into late fall before I winterized it.

I made the mistake of going away one fall leaving my garden hoses with water in them. We had an unexpected cold snap and I got back to find burst brass fittings. It was a good and in my case not too expensive lesson.

 

[wwillson]

Tonight is supposed to dip down to 28F...my boat is still sitting on the water (on a lift, out of the water, but under a cover). Obviously the water temp is still well above freezing...but with the boat sitting 2 foot off the top of the water, it makes me nervous.

You have a large amount of mass that needs to be cooled in your favor and you'll only be around 28F for a couple hours. The lake water will remain well above freezing as will the mass of the engine. Your block will not freeze tonight.

 

[DriveHard]

This would be useless.

I'm quite certain it would not be useless. MANY folks have kept an engine from freezing by throwing an incandescent light bulb in the engine bay. My batteries and charger (15 amp) are sitting in that closed engine bay with a fabric cover over the boat. The heat generated by the charger and batteries would certainly do something to keep that bay area above freezing...no doubt at all.