Antifreez

[scatgo]

Any reason why people use RV antifreeze to winterize there inboard?

 

[ThomW]

To keep the block from rusting, freezing, and/or cracking. If water is left in the engine block, it can freeze, expand, and crack the block.

There are 2 schools of thought. One group says just drain the block and hoses of all the water and the engine is good to go for the winter....as air can't freeze.
The other group prefers to drain the block and then add antifreeze to protect it against rust forming inside the block and/or protect your block if you missed a little bit of water.

Either one will work, but the big mistake is just pumping antifreeze through without draining the block first. Then you just have watered down antifreeze that will end up freezing anyway.

 

[Stinnett21]

RV antifreeze is safer for humans and the environment as in the spring you will start your engine and pump gallons of it into the local waterway.

 

[scatgo]

Good info thanks. FYI. I just stated looking into a few RV antifreezes and the all have a waring not to use to winterize boat engines. It is a lot cheaper to but why would they say not to use for winterizing?

 

[Scott Danforth]

Good info thanks. FYI. I just stated looking into a few RV antifreezes and the all have a waring not to use to winterize boat engines. It is a lot cheaper to but why would they say not to use for winterizing?

because it still freezes solid.

you need the -100F rated

 

[Lou C]

Yep I tested that stuff (-50 or -60) and it gets hard @ zero degrees F. I don't think it belongs in a cast iron engine. Also West Marine has a chart to tell you what temps you can use them, if it gets colder than 20*F I wouldn't use either of those, only the -100. I have used -100 or I mix up a batch of 50/50 Sierra PG antifreeze with water and check it with a refractometer. It is cheaper but takes time to mix vs just using the -100. It is about $7 a gallon cheaper than the -100, $14 vs $21. I use 4 gallons so I save $28 each year.

 

[muc]

Please note that a few years ago MerCruiser changed from recommending antifreeze for offseason storage to it is now required for offseason storage.

-50° pink antifreeze will freeze solid at lower temps, but it won't expand enough to burst a copper pipe until it gets colder then -50°. That's why it's called RV or pool antifreeze.

Fun fact: The better marine service providers buy 100% polypropylene glycol antifreeze with corrosion inhibiters. If you mix 1 gallon of 100% with one gallon of water, you get 2 gallons of -100°. If you mix those 2 gallons of -100° with 2 gallons of water you get 4 gallons of -50°.

If you see a marine service shop using the pink nontox in engines ---- you just found a crappy, only cares about profit service provider!

 

[scatgo]

because it still freezes solid.

you need the -100F rated

Antifreeze that will freez well ubove its advertised rating!?!? Who would have guessed. Now you all know why I consult you all on everything. Lol thanks again people.

 

[Lou C]

It's all a question of what it is designed to do. The -50 and -60 antifreezes are designed to be used in a narrow range of temps, like 32*F down to maybe 15*, this is not for extreme winter temps. If your temps get to zero that's a gamble not worth taking IF any water was still in the block. The -100 gives you a wide marin of safety, as does the 50/50 mix of Sierra PG antifreeze I mix up myself.

 

[Baylinersmitty]

I have had boats all my life but just recently bought my first inboard outboard. My boat has a 4.3 Mercruiser engine. I live in middle Georgia where the temps rarely get too much below freezing. There many days during the winter where I may want to take the boat out for an afternoon ride. My question is; what is the lowest temp I need to monitor before draining the water out of my engine? My boat is under a full cover and also under a canopy. It is supposed to be 27 degrees F in a couple of days. Don't know how long the temp will be below freezing. I see boats like mine sitting in slings in boat houses all the time during the winter. Do these people winterize every time we have a cold snap?

 

[Lou C]

I’d at least drain it. 27 degrees for more than 2-3 hrs might freeze what’s in the block & manifolds

 

[Scott Danforth]

I have had boats all my life but just recently bought my first inboard outboard. My boat has a 4.3 Mercruiser engine. I live in middle Georgia where the temps rarely get too much below freezing. There many days during the winter where I may want to take the boat out for an afternoon ride. My question is; what is the lowest temp I need to monitor before draining the water out of my engine? My boat is under a full cover and also under a canopy. It is supposed to be 27 degrees F in a couple of days. Don't know how long the temp will be below freezing. I see boats like mine sitting in slings in boat houses all the time during the winter. Do these people winterize every time we have a cold snap?

It freezes in Florida and Texas. It definitely freezes in Georgia

Many people that have boats hanging in boat houses have bilge heaters

If your boat is in the water, it's going to be fun until the water starts to freeze

 

[Scott06]

I have had boats all my life but just recently bought my first inboard outboard. My boat has a 4.3 Mercruiser engine. I live in middle Georgia where the temps rarely get too much below freezing. There many days during the winter where I may want to take the boat out for an afternoon ride. My question is; what is the lowest temp I need to monitor before draining the water out of my engine? My boat is under a full cover and also under a canopy. It is supposed to be 27 degrees F in a couple of days. Don't know how long the temp will be below freezing. I see boats like mine sitting in slings in boat houses all the time during the winter. Do these people winterize every time we have a cold snap?

If it is five easily accessible drain plugs like on mine , drain the water after each use, takes five minutes. No reason to screw around relying on power to keep a heater going

 

[OhioRiverFloater]

You don't really need antifreeze, you can just pull the plugs & let the water drain but if there is a small place that holds water it will break so we use an antifreeze flush just to be sure that we are safe from freezing. The RV antifreeze is pet & environmentally safe so it's better to use I wouldn't want a neighbor to accuse me of poisoning their pet from liquid draining from my boat.

 

[scatgo]

It's all a question of what it is designed to do. The -50 and -60 antifreezes are designed to be used in a narrow range of temps, like 32*F down to maybe 15*, this is not for extreme winter temps. If your temps get to zero that's a gamble not worth taking IF any water was still in the block. The -100 gives you a wide marin of safety, as does the 50/50 mix of Sierra PG antifreeze I mix up myself.

I dont mean to sound like a jerk but if it says - 50 antifreeze it should not freeze before -50. I have read some reviews on marine / RV antifreeze where people suffered expensive damage because they expected the antifreeze to work down to -50. IMHO it is extremely misleading and should not be allowed.

 

[Scott Danforth]

I dont mean to sound like a jerk but if it says - 50 antifreeze it should not freeze before -50. I have read some reviews on marine / RV antifreeze where people suffered expensive damage because they expected the antifreeze to work down to -50. IMHO it is extremely misleading and should not be allowed.

RV antifreeze is rated at the burst temp. Not the temp it freezes solid. However the temp a copper pipe bursts open

 

[Lou C]

Ok it will freeze but not expand that’s what it says…however….what if all the water didn’t drain? No safety margin….also read West Marine’s advisory on the use of antifreeze, they make it very clear…

 

[airshot]

RV antifreeze is safer for humans and the environment as in the spring you will start your engine and pump gallons of it into the local waterway.

I used normal antifreeze for years but always trapped it when draining and flushed it before heading to the lake. Better rust protection with regular antifreeze, but you must handle/ dispose of it properly !!!

 

[tank1949]

RV antifreeze is safer for humans and the environment as in the spring you will start your engine and pump gallons of it into the local waterway.

great idea, unless he can recycle and use again. Everything is getting too expensive.

 

[Lou C]

I might recycle my PG stuff this spring, just clean the bilge first, put in the plug, drain then put a bucket under the garboard drain, I use about 4 gallons every year.