Does the antifreeze you use really matter?

[DanOnTheBoat]

So bought antifreeze to winterize my boat this year. It's the winterproof all purpose -50 pink antifreeze. As I was reading in the side label of it it said that it's OK to use it for boats... a few lines away it stated "This product is not designed as a heat transfer fluid for closed loop systems or as disposal for internal combustion engines". Should there be a problem if I use it in my inboard boat engine?

 

[alldodge]

it stated "This product is not designed as a heat transfer fluid for closed loop systems or as disposal for internal combustion engines".

This is there so folks won't put it in a cars radiator or boats with heat exchangers.

And BTW, don't post in FAQ area

 

[Kosmofreeze]

The -50 PINK stuff contains ethanol and propylene glycol. I run the engine on fresh water (muffs) until it comes up to temp - thermostat opens. Then I put 4-5 gallons of PINK in a bucket the hook to bucket up to my muffs and run the engine (Volvo-Penta 5.7) until I see PINK coming out the exhaust. Then I know that the PINK has displaced all the fresh water in the block and hoses. Then I pull all the hoses (raw water intake and ouput) and open the block an riser drains to drain the PINK from the engine. Not much PINK remains in the engine. I'm not too worried about the remaining ethanol in the hoses ... most of it drains and that which remains evaporates. Probably a 'belt and suspenders' approach to winterizing but the Minnesota winter can get chilly ... gives me peace of mind.

 

[Lou C]

How cold are your anticipated temps? Take a look at West Marines guide to marine antifreezes it explains what to use based on temperature….

 

[alldodge]

I run the engine on fresh water (muffs) until it comes up to temp - thermostat opens. Then I put 4-5 gallons of PINK in a bucket the hook to bucket up to my muffs and run the engine (Volvo-Penta 5.7) until I see PINK coming out the exhaust. Then I know that the PINK has displaced all the fresh water in the block and hoses. Then I pull all the hoses (raw water intake and ouput) and open the block an riser drains to drain the PINK from the engine.

Your motor is safe because you drained everything, but running 4-5 gallons thru engine pump does not displace ALL the water

 

[DanOnTheBoat]

I live in Ontario, Canada, where temperatures can drop as low as maybe -25°C on the coldest days. I've watched several videos where people winterize their engines by first warming them up and then draining all the water. To ensure no water is left behind, they use an air compressor to blow out the hoses completely. After that, they pour antifreeze into the rubber hoses until they see it flowing out of the drain holes, ensuring the system is fully protected from freezing. They either leave the hoses unclamped or they put them back.

 

[Kosmofreeze]

Your motor is safe because you drained everything, but running 4-5 gallons thru engine pump does not displace ALL the water

I acknowledge that there may still be some water remaining, but when I pull the hoses and remove the plugs all I typically see is PINK coming out. If there is water remaining, it ain't much and it's in a place that has plenty room to expand when it freezes without hurting anything.

 

[Lpgc]

I'm in England, we will definitely have freezing temperatures but we're not likely to see temperatures much below -10degC (14degF) but it's still best to plan for -20C (-4F) and if we're doing that we might as well plan for the coldest temps antifreezes seem to offer protection against which are around -30C (-22F) with a 50/50 mix of water and antifreeze. This will be the first time I've winterised my boat. I mentioned how I was thinking of winterising my Ford / OMC Cobra / VolvoSX setup on a different thread...

For the engine itself - Drain as much water out of the engine as I can by disconnecting the lower pipe to the water pump (or maybe disconnect that pipe from the thermostat housing), remove the thermostat housing, fill the block with antifreeze. Turn the water pump by rigging it to an electric drill to make sure the remaining water and the antifreeze I just put in are thoroughly mixed.

For the exhaust manifolds - disconnect pipes from the thermostat housing and hold them low until nearly all the water has come out, hold them high and fill with antifreeze until coloured water/antifreeze mixture comes out of the exhaust.

For the PAS cooler - disconnect water pipe at either the cooler or the (internal) raw water pump, pour antifreeze into the PAS cooler until coloured water flows out of the water intakes on the drive.

For the internal raw water pump - hold either the intake pipe from PAS cooler or the output pipe to the thermostat housing low to drain as much water as possible, then hold both pipes high and fill with antifreeze.

Leave all the above full with mostly antifreeze and a bit of fresh/river water but hopefully with a very high concentration of antifreeze.

Change the engine oil and transmission fluid.

Leaving wet parts full with antifreeze mix seems a surer way of protecting against freeze damage than trying to drain every last bit of water from the engine and other components (as long as the the antifreeze is properly mixed with any water), plus the antifreeze could have corrosion prevention properties so be better for components than leaving them dry?

Could neat antifreeze (instead of a mix of water and antifreeze) cause any problems with any components in the engine such as the water pump seals etc?

Does all the above seem a good plan?

 

[Lou C]

I acknowledge that there may still be some water remaining, but when I pull the hoses and remove the plugs all I typically see is PINK coming out. If there is water remaining, it ain't much and it's in a place that has plenty room to expand when it freezes without hurting anything.

While it may be pink it could be diluted and you don’t know how close to freezing it would be unless you take a sample & put it in a freezer at zero F or check it with a refractometer. I mix my own PG antifreeze using Sierra PG engine antifreeze. Cheaper & better.

 

[Lou C]

As far as winterizing I I manually drain the engine & manifolds & raw water intake hose & then back fill with my mix of Sierra AF & water (-26*F) via the hoses. After engine & drive oil is changed and engine fogged. After spring start up and the AF washes out I see no rusty water coming out the exhaust. 22 years doing it this way, same block raw water cooled in salt water.

 

[Lou C]

Also note to all:
When buying AF for winterizing keep in mind the way storage AF is rated; burst temp is not the same as freeze temp. I do not want AF getting solid inside a cast iron engine even if it doesn’t expand. So ignore burst protection and go by freeze protection. -50 & -60 get solid at about 10* & 5*F respectively. I won’t put that in my engine since we get temps down to zero, so I’ve used -100 (burst) which won’t freeze till -45 or so but now I mix my Sierra to -26 freeze protection which is more than adequate. And cheaper than -100 burst.

 

[tpenfield]

A couple of points . . .

1) The rating on the anti-freeze (such as "-50") is a pipe burst rating, which is a plumbing industry rating as to when a copper pipe will burst from freezing. The liquid actually begins to freeze long before reaching the pipe burst rating. -25˚C will be close to the temperature when plastic parts in the cooling system may be damaged when using the -50.

2) There are 2 types of winterization anti-freeze . . . 1 that contains alcohol and another that is pure Poly-Glycol (PG). The pure PG type is best for engine winterization and the type containing alcohol is fine for plumbing systems. The newer marine engines tend to have more plastic parts on the raw water intake side. So, using the pure PG type may be important if you have a newer engine. The type for engines will specifically state so on the product label.

 

[airshot]

In reality it depends on how you dispose of the antifreeze when your done with it. Pink stuff is used for those that will pump it back in the lake in the spring, if you properly dispose of it before putting your boat in the water in the spring you can use regular auto antifreeze . I used the regular antifreeze (green stuff) and drained and flushed the engine before launching in the spring as I like the added rust protection the pink stuff does not have.
After changing the oil in the fall, I pulled the thermostat and drained the block and manifolds. Then filled the block and added antifreeze to the manifolds and into the supply hose from the water pump to flush and get rid of any water left in the engine. Let it set in there to prevent rust. In the spring drain and flush. Takes about a half hour all together, never had an issue in decades of doing it that way. Sucking antifreeze up thru the water pump has always been a gamble !

 

[JASinIL2006]

I acknowledge that there may still be some water remaining, but when I pull the hoses and remove the plugs all I typically see is PINK coming out. If there is water remaining, it ain't much and it's in a place that has plenty room to expand when it freezes without hurting anything.

If you're draining after running the pink stuff in through the muffs, it doesn't matter much if the antifreeze that comes out is diluted or not. Many of us just skip the antifreeze part and drain the engine and related hoses, which also protects against freezing.

The problem comes when folks run in the antifreeze and then leave it, thinking the engine is protected. Those people often show up here in the spring asking why their engine oil is milky and squirting out of the engine.

 

[DanOnTheBoat]

Got it so it doesnt really matter which antifreeze I use? I could just drain the block but I want to be extra sure that there wont be any water in there that could freeze. My boat is around 35 years old but the motor runs like its new. Don't want to risk ruining a good motor...

So would it be better to leave the antifreeze in the engine over winter?(I saw a lot of people that do that). Or is it recomended to drain the antifreeze out of the block as well?

This is the one I was talking about that I got

 

[Lpgc]

The problem comes when folks run in the antifreeze and then leave it, thinking the engine is protected. Those people often show up here in the spring asking why their engine oil is milky and squirting out of the engine.

Not sure what you mean. I understand the antifreeze has to be above a particular concentration mixed with any remaining water but do you mean too much antifreeze in the mix will damage the engine when it is started in spring?

Another question to all - If the cooling system isn't airtight (and it isn't) do some antifreezes evaporate out of the mix leaving behind just water that will freeze? Is that why glycol types are preferred over alcohol types?

 

[Lou C]

Got it so it doesnt really matter which antifreeze I use? I could just drain the block but I want to be extra sure that there wont be any water in there that could freeze. My boat is around 35 years old but the motor runs like its new. Don't want to risk ruining a good motor...

So would it be better to leave the antifreeze in the engine over winter?(I saw a lot of people that do that). Or is it recomended to drain the antifreeze out of the block as well?

This is the one I was talking about that I got
View attachment 402031

How cold is your lowest temp? If zero I wouldn’t use that…

 

[DanOnTheBoat]

Yeah temps here in Ontario get below 0 probably around -25 *C on a coldest winter day.

Is this any better?

 

[nnl1987]

A better question is: I assume you are running in fresh water (being from Ontario myself). If that is the case I would drain the block, put the plugs back into the block run antifreeze through it then drain the antifreeze out and leave the block drain plugs out. I regularly see weeks of -40s -45s C and to me its just not worth the risk. $50 for antifreeze versus a new block..

Since I assume it's a fresh water boat the benefits of leaving the antifreeze in for rust inhibitors is not as pressing as a salt water boat.

 

[DanOnTheBoat]

Yeah I always run my boat in fresh water. Do you do that procedure? Leaving the drain plugs out over winter?

If I do drain the antifreeze out of the block wouldnt there be moisture buildup or would it just evaporate or escape through the opening of the drain holes?

Just want to do it right, it's my first boat and my first time winterizing it and don't want to ruin it.