Antifreeze...1/2 mixed or straight?

Scaaty

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May 31, 2004
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Does anyone know the freezing temp of straight AF? Reason is, we rarely get a good freeze here in the Pacific Northwest where were at down at sea level on Puget Sound, and this is ONLY put in the Motor/Mans for rust prevention after draining over the trailer months. Why add water?
 

ZmOz

Captain
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Aug 13, 2003
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Re: Antifreeze...1/2 mixed or straight?

Scaaty said:
Why add water?

Because antifreeze costs $10+ per gallon, and water is basically free.
 

Bondo

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Apr 17, 2002
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Re: Antifreeze...1/2 mixed or straight?

Straight Anti-freeze,...... Freezes at a relatively High Temp,.......

The Coldest Possible protection comes at a 50/50 Mix..........

And,..... Tommays has some Pretty Solid Proof that the Anti-Freeze is Unnecessary,+ a Waste of Time,+ Money for Rust Prevention..........
It's over in the Engines forum......
Have a Look,........http://forums.iboats.com/bbBoard.cgi?a=viewthread;fid=24;gtid=1178457
 

Bob_VT

Moderator & Unofficial iBoats Historian
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May 19, 2001
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Re: Antifreeze...1/2 mixed or straight?

Straight antifreeze can freeze as warm as -8F

a 50/50 mix will get you to -35 to -40F

a 70/30 will get you -70 to -84F

RV antifreeze is "non-toxic" if you have pets around.

In the past years I have stripped my i/o blocks dry and never had a crack.
 

John_S

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Jun 21, 2004
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Re: Antifreeze...1/2 mixed or straight?

Don't use Ethelyne Glycol, use a product such as BanFrost 2000. You can use it straight for the max temp protection (-100F). It is specific for winterization and has rust prohibitor pkg.
 

Scaaty

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Re: Antifreeze...1/2 mixed or straight?

I was just curious. We have 104 boat slips in our Marina, 1746 different opinions, 600 different boats (4 myself) here all together probably, 1000 motors. Makes for great dockside/dog walk chat. Myself, I just run to temp (350I/O), after old oil out and new, fog while running Saltaway through. I drain the block, hoses off, and leave the block dry. BUT! Most (all) of my rusted through areas over the years have been bottom of the Stat housing, and of course, bottom on the Mans. I liberally spray WD in the stat housing, and pour AF in the mans. Makes me feel warm and fuzzy over the winter, even if it is a waste of time. On the Gas Tank full or M/T (before it gets mentioned anyway, and I also TAPE off all the vents), well, 4 boats (this one has a 90 gallon tank), and 8 motorcycles, plus the various other engine run implements around the Dogpatch, I'm overwhelmed. So on the weekly trips to town (early retired, and want to stay that way!), I pick up 5 or 10 gallons of gas, Staibil (ya just never know when something might sit for MORE than one year, and at $10 for 80 gallons, why not?), add a little Marvel Mystery oil (might help coat the tank and prevent corrosion--again, the warm and fuzzy thing), and slowly fill up the big boat. Other stuff gets siphoned out, to the van, and replaced with fresh as I get around to it, then either run it, ride it, or for lack of a better word, F#%k it.
PS. All the crap out the back of the boat is captured and disposed off properly. We take our water and clean environment seriously here in the PNW. Although the tree huggers drive me nuts, so things do make sense.
 

Bill Adkins

Seaman
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Sep 27, 2006
Messages
68
Re: Antifreeze...1/2 mixed or straight?

Hi Guys, I vote for 50/50. I have worked with Mercedes Benz for over 30 years and they have always used a guide of 50/50. Water has a higher efficiency for transfer of heat than the normal coolant you might use so straight coolant doesnt work as well as a cooling medium in an engine. I guess 50/50 is the most advantagous for the job being attempted. Just my 2 cents worth.
Bill
 

Texasmark

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Dec 20, 2005
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14,896
Re: Antifreeze...1/2 mixed or straight?

Bill, you are correct. What the 50% does over straight water is (with the pressure cap) raise the boiling point of the fluid so that your engine can run hotter (when times get tough) without boiling out your coolant.

Water has the best thermal transfer of any fluid that I looked up, when I was in the business.

The water should be distilled so as to not contain any chemicals that could attack your metallic parts.

Using an over flow container and venting radiator cap keeps the coolant chamber completely full of fluid and doesn't allow for any air which contains oxygen which is an oxidizer and causes corrosion.

Mark
 

JasonJ

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Aug 20, 2001
Messages
4,163
Re: Antifreeze...1/2 mixed or straight?

All antifreeze does is raise the boiling point and lower the freezing point of water. It does not tranfer heat very well. I have seen enough people ruin their engines by running straight antifreeze to know this is true. 50/50 is the best way to go....If you are running a closed cooling system in a boat. If your system is open, then just flush with fresh clean water and be done with it...
 
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