Does the antifreeze you use really matter?

[nnl1987]

There would I assume be some slight moisture during the fall and spring when it's cycling between frozen hoth temperatures and springtime. But it evaporates or escape through the openings. I have been winterizing mine this way for a couple of years. Air doesn't freeze as many have said before on this forum (although my face does when the air hurts to breath when it's so cold).

Make sure you get a manual and get all the drain plugs there could be as little as 4 or I've read 6 on this forum on some inboard/outboard setups.

 

[DanOnTheBoat]

There would I assume be some slight moisture during the fall and spring when it's cycling between frozen hoth temperatures and springtime. But it evaporates or escape through the openings. I have been winterizing mine this way for a couple of years. Air doesn't freeze as many have said before on this forum (although my face does when the air hurts to breath when it's so cold).

Make sure you get a manual and get all the drain plugs there could be as little as 4 or I've read 6 on this forum on some inboard/outboard setups.

Fair enough, okay then I will probably consider doing it that way, with the plugs out. If i do do it that way Im assuming any antifreeze would work since Im still going to drain it out of the engine?

If Im not wrong I only have 2 drain plugs(87 4 cylinder merc 120 inboard).

 

[nnl1987]

Fair enough, okay then I will probably consider doing it that way, with the plugs out. If i do do it that way Im assuming any antifreeze would work since Im still going to drain it out of the engine?

If Im not wrong I only have 2 drain plugs(87 4 cylinder merc 120 inboard).

I still choose to put -73 C (-100 F) stuff in my block. I don't like taking any chances with how cold it gets where I live. I like the peace of mind. If you feel comfortable with the -50 stuff then by all means can use it.

Yes it might seem silly to just drain it out afterwards after immediately putting it in (any low spots in the cooling passages will still have antifreeze in it). But I use it in other things after that are less valuable.

As a side note, not entirely sure if the design of engine blocks have low spots in them. I shrug my shoulders.

Also take a coat hanger or some other stiff wire and poke right into the block drains they can get all built up with crud and make you think you got all the water out. I still can't comment if your block would have 2 drains or not. Some other members might be more knowledgeable.

 

[DanOnTheBoat]

I still choose to put -73 C (-100 F) stuff in my block. I don't like taking any chances with how cold it gets where I live. I like the peace of mind. If you feel comfortable with the -50 stuff then by all means can use it.

Yes it might seem silly to just drain it out afterwards after immediately putting it in (any low spots in the cooling passages will still have antifreeze in it). But I use it in other things after that are less valuable.

As a side note, not entirely sure if the design of engine blocks have low spots in them. I shrug my shoulders.

Also take a coat hanger or some other stiff wire and poke right into the block drains they can get all built up with crud and make you think you got all the water out. I still can't comment if your block would have 2 drains or not. Some other members might be more knowledgeable.

Got it appreciate the advice and help! Seems like draining the block is better than leaving it full with even antifreeze. What kind of -100 antifreeze do you use? Majority of what I'm finding online are all rated -50.

 

[nnl1987]

Got it appreciate the advice and help! Seems like draining the block is better than leaving it full with even antifreeze. What kind of -100 antifreeze do you use? Majority of what I'm finding online are all rated -50.

Ehh sorry. That was burst rating.

Mercury - Mercruiser 92-8M0073203.
Says Provides freeze protection within a range of ‑58ºF to ‑63ºF (‑50ºC to ‑52ºC)

 

[JASinIL2006]

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?

The problem with running antifreeze into an engine via the muffs is that the engine's cooling jacket and hoses are already full of water. When antifreeze is introduced via the muffs, the water in the engine dilutes it. So the water-antifreeze mix that exits the engine may look pink, but there is no good way to know what the concentration of antifreeze is in the fluid remaining in the engine. If you drain the engine after using the antifreeze, you don't need to worry about the concentration, because there is nothing (or very little) left in the engine to freeze.

I don't think there is any danger from having too high of a concentration of antifreeze.

 

[Scott Danforth]

If only we had this in a sticky...... wait....we do.. https://forums.iboats.com/threads/winterizing-inboard-and-i-o.770207/

 

[Lou C]

The basic problem with raw water cooling and running in antifreeze is this:
your cooling system has excess capacity to cool the engine and exhaust,
the manifolds & elbows get full flow from the 'stat housing (except in Merc warm manifolds, not until the 'stat opens) and the engine 'stat, opens and closes to maintain its set temp. The engine 'stat functions a gate valve.
So if the engine is idling on a cool fall day, it is unlikely to open all the way to allow a full exchange of AF, due to the block still being full of water. There is no load on the engine to build heat in the water, so the stat stays closed or mostly closed. Remember for the stat to open the water has to get hot, for the water to get hot, the engine has to be under load. Idling is not putting the engine under any load. My engine idles at 160* and the manifolds and elbows are only at 90-100* F, at idle, hardly warm. You will wind up with AF in the exhaust and a diluted (but unknown & probably inadequate) concentration of AF in the block.
People will say, but I saw pink coming out the exhaust....yes you did but that was all or mostly by passing the engine, because the engine is not hot enough to open the stat!
This is why you should choose one of these options:
drain it all down, and leave it, some prefer this....
drain it all down and back fill with AF via the hoses....I like this....
drain the block and then run in the AF....to me not worth it, if you're draining just back fill!
I prefer manual drain and manual fill, you know it's drained, and manual fill is less messy and uses less AF and there is no chance of burning the impeller if you don't suck up the AF fast enough because remember the water hose puts water in under pressure, the AF is gravity feed unless you put a pump on your winterizing tank.
As I said in a previous post, marine AF is rated in terms of burst temp not freeze temp. What that means is the AF will get hard at a certain temp but not expand. Having said that, I do not like the idea of AF getting hard in a cast iron block, so you want to go by FREEZE temp not Burst temp. Safer!

 

[Lou C]

Sites-WestMarine-Site

West Marine

www.westmarine.com

read this, you'll see if you get zero or below, do not use -50 or -60, use -100! remember those are burst temps....

 

[dingbat]

Enough to make your head spin.
Glad I own outboards........

Back before I saw the light, other than the 1st year when I pulled the thermostat housing and poured a bunch of anti-freeze in the motor, I simply pulled the drain plugs (block) and let it drain on the way home from fishing once temps got below freezing.

Having said that, the record low temp for the area is -7 F . The average low temp in January is 29F.

 

[briangcc]

Two marinas that have done the bulk of service on my boats do NOT use antifreeze in them. Period. Volvo and Merc authorized dealers. They warm them to temp then drain the blocks leaving it dry over the winter.

The selling marina who winterized my boat last year used pink antifreeze. Different Merc dealer.

My personal preference, barring whatever Volvo or Merc says, is to leave the block drained. 12 years on my FourWinns with original block - no issues - always drained. I like those odds.

**I live in WNY so we get cold temps.

 

[JimS123]

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

That is NOT the one you need. Give it to someone else that has an RV.

There are 2 kinds of "pink stuff". One is for toilets, sinks and potable water systems. The other is for engine cooling systems. You got the former. It's also the cheaper of the 2 varieties.

Lots of bad talk about pumping AF thru and then stopping when the exhaust comes out pink. The logic is that there is still water present.

Personally, I used t drain, pull the TS, fill manually, yada yada. Then, I bought the kit and then did the flush. Easy peasy, while the old method was a pita. Having said that my boats are attached garage kept and the lowest temp I EVER saw was 25F.

This whole concept is one of the main reasons I got rid of my ;last I/O and switched to a 4-stroke OB. Don't even neeeeed to winterize...

 

[Lou C]

If you’re in fresh water you may not need antifreeze but us salt water people have a whole different view on it…just like coating your trailer springs with grease & corrosion X. Like I said I never get rusty water out the exhaust during spring start up. 22+ years on the same short block in the salt…

 

[Lpgc]

The problem with running antifreeze into an engine via the muffs is that the engine's cooling jacket and hoses are already full of water. When antifreeze is introduced via the muffs, the water in the engine dilutes it. So the water-antifreeze mix that exits the engine may look pink, but there is no good way to know what the concentration of antifreeze is in the fluid remaining in the engine. If you drain the engine after using the antifreeze, you don't need to worry about the concentration, because there is nothing (or very little) left in the engine to freeze.

I don't think there is any danger from having too high of a concentration of antifreeze.

I'm a little late to reply and the thread has moved on, I agree with you, but I was talking draining most of the water from my block, manifolds, PAS cooler and raw water pump and pouring in neat antifreeze. You did answer my question about whether neat antifreeze could damage anything such as my water pump / seals / etc. Thanks for the info.

 

[Lpgc]

just like coating your trailer springs with grease & corrosion X

I didn't think about the trailer springs lol! I've only used my trailer in fresh river water, is this something I should be concerned about?

 

[Lou C]

In fresh water probably not, here the only trailers that last are either hot dip galvanized or aluminum. Although some fresh water can be pretty corrosive…

 

[Lou C]

I'm a little late to reply and the thread has moved on, I agree with you, but I was talking draining most of the water from my block, manifolds, PAS cooler and raw water pump and pouring in neat antifreeze. You did answer my question about whether neat antifreeze could damage anything such as my water pump / seals / etc. Thanks for the info.

Wait a minute…when you say neat antifreeze to you mean full strength not mixed with water? Better check that. If it’s a marine or RV antifreeze you can just use it those are premixed with water. But if it’s like full strength automotive antifreeze, they will actually solidify at a higher temp than if it were mixed with water…

 

[Lpgc]

Wait a minute…when you say neat antifreeze to you mean full strength not mixed with water? Better check that. If it’s a marine or RV antifreeze you can just use it those are premixed with water. But if it’s like full strength automotive antifreeze, they will actually solidify at a higher temp than if it were mixed with water…

I did mean using neat automotive antifreeze, though maybe not being able to remove all the water (particularly from the engine) so there might still be a mix. But, yes, my question was about if I did get all water out would neat antifreeze be a problem. Now you've said neat antifreeze could be a problem I'll part mix antifreeze with water before putting it in. I didn't know neat automotive antifreeze turned solid if not mixed with water. Most stuff shrinks when cooled or turning from liquid to solid, water ice is different because it expand and it's the expansion that can crack blocks etc. How would neat antifreeze solidifying be a problem (does it expand like water turning into ice)?

 

[Scott Danforth]

. But if it’s like full strength automotive antifreeze, they will actually solidify at a higher temp than if it were mixed with water…

Having done the experiment to verify the freezing temps in college nearly 40 years ago. each brand has a slightly different volumetric ratio as there is already some water in their EG mix.

read the labels, there will be a chart on the back of the bottle.

It was prestone that we tested, full strength (100% EG by volume) freezes at -86F. 50% mix ratio by volume freezes at about -34F.

we also tested boiling point and thermal conductivity. as the percentage of EG goes up, the boiling point goes up, however the thermal transfer rate goes down

Having worked in the marine heat exchanger market a while back as well as the diesel engine market before that. I can also attest that thermostats will never let antifreeze and water mix in the block if the antifreeze is so much as 3 degrees colder than the engine.

since no one heats the antifreeze to 160-180F..... in those block-busting kits, we get a rash of broken block threads every spring.

so the simple answer. drain all the water from the block/heads/exhaust/lines/etc. like the manual calls out...... then it wont freeze. now if you want to add EG or PG do so. Just make sure it is not just RV plumbing mix (not enough freeze and corrosion protection). it has to be the engine storage mix (which is the same as boiler AF) if you add EG, you need to drain it fully come spring before you summerize as it is toxic. PG can be left in.

 

[ChooChooSnakeMan]

I recently added a post under the Volvo Penta section about winterization. The input I got was very helpful. One thing that stood out to me was "air don't freeze"! My opinion and what my Volvo Penta service dealer did last fall is that antifreeze is not needed in a fresh water boat if the factory instructions are followed to the letter for winterization / storage of the engine. I'm going to open the (4) four drain plugs (poke them with wire to make sure they are open, take (4) hoses off, make sure my freshwater tank is empty, remove the portable toilet, trim the outdrive all the way down and that's it. I'll leave the plugs and hoses disconnected until late spring when I'll hook everything back up. If I wanted corrosion protection of anti freeze I'd just pour it into the hoses until it came out of the drain plugs and call it good. I don't see a need to do this in a freshwater boat but it wouldn't hurt anything. Hurry up boating season 2025!