Merc 3.0 Sterndrive Winterizing Question

[HiTekRedNek]

I've been looking at bunches of youtube videos about winterizing my 3.0 L. Many of these self-proclaimed experts recommend using -50 degree RV/Marine water system antifreeze in the water jackets and manifolds of Merc Sterndrives. The thing is, I was looking at this very type of anti freeze and the label clearly states that it's NOT for winterizing marine engines. My Merc engine manual specifies propylene glycol based antifreeze for winterizing. I found that Peak makes PG based antifreeze however it only provides freeze protection to -25 deg. It does and will get colder than that here in Northern Wisconsin. So I'm asking for suggestions. What do the big boys use? Thanks in advance!

 

[Scott06]

I've been looking at bunches of youtube videos about winterizing my 3.0 L. Many of these self-proclaimed experts recommend using -50 degree RV/Marine water system antifreeze in the water jackets and manifolds of Merc Sterndrives. The thing is, I was looking at this very type of anti freeze and the label clearly states that it's NOT for winterizing marine engines. My Merc engine manual specifies propylene glycol based antifreeze for winterizing. I found that Peak makes PG based antifreeze however it only provides freeze protection to -25 deg. It does and will get colder than that here in Northern Wisconsin. So I'm asking for suggestions. What do the big boys use? Thanks in advance!

crack open a beer cause this will get to be worse than a oil thread...

the cheaper RV marine water system ones are alcohol based and do not have corrosion in inhibitors in them. What marinas doing hundreds of boats will use is PG in a huge tub (100's of gallons) and check the strength pf the PG. The PG here will be like Dowfrost and is meant for industrial chilling systems that run below freezing.

Here's where if you ask two guys you will get three different answers that all work...

There are two drain plugs on the 3.0 easy to get to drain first. then you can fill or not fill with af if you want. Some guys back fill w/ -100f PG AF intended for marine use. Some like me drain the water, then I take the hose off from the drive to thermostat housing I use a gallon to back flush the PS cooler through drive, and dump some in each water jacket on block and manifolds to rinse out any residual. I do this with the cheap stuff and in Upstate NY never had an issue.

On my seadoo I rig a bucket and run 3 gallons through the engine of the cheap stuff in 10-12 years never an issue.

@Lou C has a pretty good system backfilling that he can walk you through

 

[HiTekRedNek]

crack open a beer cause this will get to be worse than a oil thread...

the cheaper RV marine water system ones are alcohol based and do not have corrosion in inhibitors in them. What marinas doing hundreds of boats will use is PG in a huge tub (100's of gallons) and check the strength pf the PG. The PG here will be like Dowfrost and is meant for industrial chilling systems that run below freezing.

Here's where if you ask two guys you will get three different answers that all work...

There are two drain plugs on the 3.0 easy to get to drain first. then you can fill or not fill with af if you want. Some guys back fill w/ -100f PG AF intended for marine use. Some like me drain the water, then I take the hose off from the drive to thermostat housing I use a gallon to back flush the PS cooler through drive, and dump some in each water jacket on block and manifolds to rinse out any residual. I do this with the cheap stuff and in Upstate NY never had an issue.

On my seadoo I rig a bucket and run 3 gallons through the engine of the cheap stuff in 10-12 years never an issue.

@Lou C has a pretty good system backfilling that he can walk you through

Thanks! I'll check it out.

 

[HiTekRedNek]

UPDATE - I visited the Old World Industries (parent co. of Peak Antifreeze) and looked up the spec sheet for their Peak/Sierra PG based antifreeze. Info on Amazon was wrong... surprise, surprise. Per the spec sheet, this product provides freeze protection to -54 F when mixed in a 60/40 AF to water mix. So I think I'll backfill the cooling system with this stuff after flushing and draining. I'd rather not leave the cooling system drained over the winter. Rust never sleeps. And neither would I... LOL! Product tech lit attached.

 

[HiTekRedNek]

UPDATE 2 - I checked out the Material Safety Data Sheet for this product (I was a Systems Engineer for many years, that's what we do). While PG based antifreeze is indeed LESS toxic than ethylene glycol based products, it is NOT non-toxic.

From the MSDS: Notify authorities if product enters sewers or public waters. Soak up spills with inert solids, such as clay or diatomaceous earth as soon as possible. This material and its container must be disposed of in a safe way, and as per local legislation.

So what does this mean to me? It means that if I backfill my cooling system for the winter with this stuff, I need to completely drain it from the system before going anywhere near the water. The drained coolant needs to be disposed of properly. While it probably wouldn't hurt anything for me to go boating with a little bit of this left in the cooling system, it's STILL not good for the environment and IS in violation of published directions for use, hence it's illegal.

I'm sharing this info for those who have their boats winterized with PG based antifreeze who may not be aware that this stuff needs to be treated just like plain old antifreeze as regards disposal. You can't just take your boat out with this stuff in the cooling system, crank it up and drive off. If you use this stuff for winterizing, please drain your system completely before your first outing and dispose of it properly.

So now I'm leaning back toward the alcohol based RV/Marine water system antifreeze. It may not have the corrosion inhibitors, but it will still displace the air in my cooling system over the winter and that should help prevent rusting and corrosion. And it won't funk up the environment.

 

[tpenfield]

A few things to keep in mind about the winterization.

Alcohol-based AF is not recommended for engines vs. PG-based AF. I have used both on my engines, but prefer to stay on the recommended course.

The temperature rating of the anti-freeze is not a freeze point, but rather a burst rating. The AF will freeze long before it gets down to the temperature of the burst rating and can/will fracture any plastic parts in the cooling system. Typically if you are anticipating temperatures below 0˚F, you will want to go with the -75˚ or the -100˚, instead of the -50˚ .

Coolant flow inside of a marine engine is not very sequential, and much of the cooling water/AF by-passes the engine and goes straight to the exhaust. therefore seeing the AF come out of the exhaust can be misleading as to the concentration inside the engine and exhaust manifold. That is why the veteran players drain the system to purge the water before adding AF, rather than merely drawing it in through the outdrive via 'muffs'.

 

[HiTekRedNek]

A few things to keep in mind about the winterization.

Alcohol-based AF is not recommended for engines vs. PG-based AF. I have used both on my engines, but prefer to stay on the recommended course.

The temperature rating of the anti-freeze is not a freeze point, but rather a burst rating. The AF will freeze long before it gets down to the temperature of the burst rating and can/will fracture any plastic parts in the cooling system. Typically if you are anticipating temperatures below 0˚F, you will want to go with the -75˚ or the -100˚, instead of the -50˚ .

Coolant flow inside of a marine engine is not very sequential, and much of the cooling water/AF by-passes the engine and goes straight to the exhaust. therefore seeing the AF come out of the exhaust can be misleading as to the concentration inside the engine and exhaust manifold. That is why the veteran players drain the system to purge the water before adding AF, rather than merely drawing it in through the outdrive via 'muffs'.

Thanks for the reply! The most important point I was trying to make was that if you fill your cooling system with PG, then you need to completely drain the system before your first outing and dispose of the used PG antifreeze properly. It's not as environmentally friendly as the manufacturers would lead us to believe. It is illegal to dispose of it into sewers or public waters.

On the other hand, alcohol based AF is environmentally safe. From Prestone's MSDS for their alcohol based Waterline Antifreeze: DOT MARINE POLLUTANTS: This product does not contain Marine Pollutants as defined in 49 CFR 171.8. So if I use the alcohol based product, I can launch my boat in the spring without polluting the environment and without the hassle of draining and disposing of PG antifreeze.

And you are absolutely right about not mistaking the burst temp and freeze temps on waterline antifreezes. The Prestone product publishes a -100 F burst temp. I have to figure that will cover me. After all it doesn't matter if the antifreeze slushes up a bit while it's in storage. It won't be slushy by the time I go to launch!

 

[Bondo]

So I'm asking for suggestions. What do the big boys use?

Ayuh,...... Not much saltwater in Wisconsin,... Rust will never be an issue for you,.....

As for winterizing,...... Air don't freeze,......
'n a drained block will never crack,.....

 

[Scott Danforth]

It does and will get colder than that here in Northern Wisconsin. So I'm asking for suggestions. What do the big boys use? Thanks in advance!

you follow the manual and pull the drive, and drain the water jacket, manifold, and J-hose. then its winterized. at least that is what I did when I lived in Wisconsin.

Then as the manual states, Optional, if you choose to add anti-freeze for corrosion inhibition, add to the thermostat housing with a funnel.

 

[ROY WILLIAMS]

I've been looking at bunches of youtube videos about winterizing my 3.0 L. Many of these self-proclaimed experts recommend using -50 degree RV/Marine water system antifreeze in the water jackets and manifolds of Merc Sterndrives. The thing is, I was looking at this very type of anti freeze and the label clearly states that it's NOT for winterizing marine engines. My Merc engine manual specifies propylene glycol based antifreeze for winterizing. I found that Peak makes PG based antifreeze however it only provides freeze protection to -25 deg. It does and will get colder than that here in Northern Wisconsin. So I'm asking for suggestions. What do the big boys use? Thanks in advance!

I was the 1978 MCM470 ,,, the fall .. did the water plugs drain it ..
take out the outdrive inspected it .. did the grease and the bellows cleaned it ...the spark plugs are one OZ of the Marvel Mystery Oil in the cylinders .the carb orifice air port is the 2 OZ MMO ...
the carb is the plastic sheet ...
I was the gasoline drain the boat tank .. then truck is the gas tank ...
northern wisconsin in the 1960-1970 -50F temps .....
I was a great engine very good ...

 

[HiTekRedNek]

Ayuh,...... Not much saltwater in Wisconsin,... Rust will never be an issue for you,.....

As for winterizing,...... Air don't freeze,......
'n a drained block will never crack,.....

I like the way you think, Bondo! Thanks

 

[HiTekRedNek]

you follow the manual and pull the drive, and drain the water jacket, manifold, and J-hose. then its winterized. at least that is what I did when I lived in Wisconsin.

Then as the manual states, Optional, if you choose to add anti-freeze for corrosion inhibition, add to the thermostat housing with a funnel.

Thanks!

 

[Scott06]

if your sea ray has the in console built in cooler like mine- put some af down the cooler drain. it generally traps some water, cracked mine on my first sea ray years ago next spring water was leaking on floor

 

[CayugaCobalt]

UPDATE - I visited the Old World Industries (parent co. of Peak Antifreeze) and looked up the spec sheet for their Peak/Sierra PG based antifreeze. Info on Amazon was wrong... surprise, surprise. Per the spec sheet, this product provides freeze protection to -54 F when mixed in a 60/40 AF to water mix. So I think I'll backfill the cooling system with this stuff after flushing and draining. I'd rather not leave the cooling system drained over the winter. Rust never sleeps. And neither would I... LOL! Product tech lit attached.

I like the way you think too. I have been going back and forth between the two pink RV antifreezes. I do drain my block first. First bought Tractor Suppy Traveler $3/gal alcohol based version and heard alcohol was bad for the rubber hoses. Then read it would be better to replace alcohol with a PolyGlycol based anti freeze. My Auto Zone has Prime Gaurd RV & marine, with Yellow label, $7/gal, but the second ingredient Ethyl Alchol, just like the $3 Traveler version, then PolyGly is 3rd ingredient and tert butyl alcohol was 4th. So it seems this Poly Gly AutoZOne yellow Prima Guard with alcohol would also hurt my rubber /gaskets hoses IF that is at all true.

Now BOTH have the First Ingredient of Water and All summer the engine is pulling Water. So why do some commentators extoll the critical importance of having Corrosion inhibitor in the Anti Freeze?

is the PolyGly the corrosion inhibitor?

 

[Buster53]

I buy 2 different antifreezes, both are pink.
West Marine sells one for $6.99 that is made for both water and engines. It is PG antifreeze that is alcohol free with added rust inhibitors.
That is what I use in my engines and air conditioning system.
For the heads and water system, I buy the RV pink from Walmart for 3.99. It is PG with added alcohol. Been doing that for years…no problems

 

[airshot]

When I had my 3.0, I just used regular antifreeze after draining the block. The idea was to push out any left over water a give some rust prevention or at least slow it down..drained it in the spring and disposed of it properly. No reason to make rocket science out of winterizing.

 

[nola mike]

So why do some commentators extoll the critical importance of having Corrosion inhibitor in the Anti Freeze?

This. If you're running warm salt water through there all summer, you think the corrosion is happening after it's been flushed with fresh water and is sitting dry in the cold?

 

[CayugaCobalt]

This. If you're running warm salt water through there all summer, you think the corrosion is happening after it's been flushed with fresh water and is sitting dry in the cold?

I still dont get it; coming from the perspective of an empyt block in the winter is better than adding any of this water based anti freeze. In my case, I am running fresh water thru the block during boating season and you are running salt water. Dont both of these cause corrosion all boating season? Is the idea not to have corrosion all year long and have corrosion prohibitor in the block during the winter?

 

[Scott Danforth]

Fresh water rust is primarily staining

Salt water rust is deep

Metal underwater rusts much more slowly than wet metal exposed to air

Air doesn't freeze until -471F

Most PG antifreeze will freeze about 0F.

Straight PG antifreeze freezes at -86F

 

[CayugaCobalt]

Fresh water rust is primarily staining

Salt water rust is deep

Metal underwater rusts much more slowly than wet metal exposed to air

Air doesn't freeze until -471F

Most PG antifreeze will freeze about 0F.

Straight PG antifreeze freezes at -86F

Thanks. Good info!