anti-freeze mixtures

[rweddy]

I was having a discussion with another engineer at work today about mixture percentages with anti-freeze.

 

He is the Porsche club and have they run 20% anti freeze 80% water. He says they do this since water has better cooling properties than anti freeze.

 

I have always ran 50/50 but he says this is a waste and not a good mixture level for Colorado.

 

Thoughts??

[Snowman]

Interesting....did the guy say who recommended to him that he run that mixture?

 

Fact: Water is able to transfer more heat than antifreeze.

 

Here's the thing about antifreeze that most people forget: It does a whole lot more than prevent freezing of the coolant mixture. Among other things, antifreeze has additives that lubricate the water pump, prevent foaming and that type of cavitation (there are other kinds...ask a diesel mechanic), prevent deposits from forming in the engine, prevent corrosion, and keep the pH pretty close to neutral.

 

If you were to reduce the mixture in your Soob, you're taking the chance that the water pump might wear out faster, that more corrosion will happen, that cavitation may happen, that the pH might go acidic, and that more deposits will form. Maybe none of that will occur, but the thing is that you don't know.

 

The first thing that comes to mind when you said that it's a Porsche club is that MAYBE, due to cooling system design and how they're driving, those guys NEED the extra heat transfer ability afforded by the weaker mixture, and they're willing to sacrifice the other things that antifreeze does. Depending on how old their cars are, maybe they were designed to run a 20% mixture. Of course, if they change their coolant more often, then the additive levels would probably be high enough that no problems would develop, but that's all guessing on my part.

 

How cold does it get where you live? How about any place that you might consider driving to? You'd have to double check, but I would venture a guess that a 20% mixture would freeze somewhere around 0 degrees F. If it gets that cold, your engine is most likely going to have a cracked block, which can really ruin your day.

 

Up here, it usually gets to around 20 below duing january, but I also sometimes drive up north where temps can reach 50 below or colder. Taking that into account, I mix the antifreeze in my cars at 75%, which supposedly brings the freeze point down around -60 or -65. Many people don't know that beyond that, a stronger mixture will actually freeze at warmer temperatures. Straight antifreeze freezes somewhere around zero if I remember correctly. Now, I know that I'm sacrificing some cooling capacity in order to prevent a freeze. However, I've never had overheating issues or even gotten my car above the normal temperature range, even in 80 degree weather with heavy loads. Maybe up over 90 degrees, some problems would develop, but I've never been there. So, I'm pretty sure that you've got plenty of cooling capacity if you run the standard 50% mixture.

 

Wow, that was a lot longer than I had initially planned.

 

I would also mention, while we're on the subject, that in my experience, the vast majority of cars on the road today have badly neglected cooling systems. If you change your coolant every couple of years and all the hoses every 4 or 5, your car will thank you for it. I won't get started on SCA's or coolant filters.

[kimokalihi]

I believe I was told by a mechanic and actually I think more than one mechanic to mix 70%antifreeze with 30%water. But I guess it could have been the other way around...But that's what I always thought.

[Setright]

So, let me get this straight...these people aren't driving air-cooled Porsche 911's ? No need to take them seriously then

 

 

Snowman has already done a good job answering, but my nerdy side wants to add:

 

Water has three times the heat capacity of anti-freeze making it more temperature stable, and giving you more time to react to an overheating engine.

It is also able to transfer heat at twice the rate of antifreeze.

 

So, yes. 99% pure water and 1% detergent to break the surface tension is the ideal in terms of heat control alone.

 

 

Living in a hot area, I would probably run 60% water. Enough to make me feel smug about optimising the cooling system, but at the same time not so weak that my engine would corrode internally.

[OB99W]

A 50% solution of glycol-based antifreeze raises coolant boiling point about 12 degrees F, aside from the previously mentioned advantages.

[bkcraun]

Water does cool better than anti-freeze. Use the minimal amount of anti-freeze needed in your area to keep the water from freezing. Usually this is a 50-50 mixture or slightly more water than anti-freeze. Warm weather areas may be able to get away with an 80-20 mixture.

[OB99W]

[...]Warm weather areas may be able to get away with an 80-20 mixture.

Or not ... for the reasons already mentioned.

[Snowman]

Or not ... for the reasons already mentioned.

 

Oh good, at least somebody does listen to me.

[OB99W]

Oh good, at least somebody does listen to me.

Yes, I read (and agree with) what you wrote, but I wonder who read what I said in post #5 of this thread.

[cookie]

For me I read the directions on the jug and the car manufacturer's reccomendations. I don't trust the Porshe club as far as I can throw a 911.

I prefer to get my advice from engineers and chemists rater than lawyers and dentists in this area. Now there are other areas I prefer to get the advice from the lawyers and dentists...

[montana105]

as those of us up here in Montana know temperatures can go to the extreme both ways but we worry more about winter.I always use the 50/50 mix in my cars,and when I know it's gonna be real cold (below -15 F) I always point my car away from the wind when parking it,have never ever had a problem with freezing much less a starting problem,doesn't hurt that i park inside at night but the car sits outside in the elements all day and has been to Alaska for 2 months without any protection and never failed me,good battery helps alot.

John

[cookie]

Up in Maine at the begining of winter the first thing you did after the oil and thermostat change was to put a hydrometer in the antifreeze and see what temp is was good to.

It's not good to have your antifreeze good for zero when it's 20 below outside.

[jib]

I run 70 water/30 antifreeze and have for years in cars that did not get exposed to temperatures low enough to freeze. The key for me is that I use a half bottle of WaterWetter in each car too. Waterwetter contains a complete anti-corrosion package, in addtion to their surfactant.

 

Also, be sure to used de-ionized water (not tap, spring or bottled water), as it is mineral free and will keep your cooling system clean. It will dissolve some of the chalky white deposits in your cooling system over time too.

 

I ran 50/50 when we lived in Saco, Maine.

 

Jack

[cookie]

I run 50-50 here in SF just like it says on the jug of anti-freeze, no real challenge for heating or cooling here. I don't even bother to test it because it would take an earthquake to get me somewhere it would freeze.

[beataru]

I run 70/30 or even 80-20 or even..... Royal purple waterwetter and a little bit of afreeze and the rest water........ 911's have way more indepth cooling systems than a little subie does... it wraps around the entire/ back to front to right front to back/ before it reenters the engine...there cooling capacity is Gigantic compared to a soob so use manufaturers specs... unless you live in the hell hole of the desert like me!

[Setright]

Any "real" 911 is air-cooled

 

 

 

(But it does carry an insane amount of oil....)

[rverdoold]

I am interested in why would you mix antifreeze with water. As here it gets well below -10 Celcius (14F) and in germany in winters even below -20 (-4F) during the nights. I just flushed my cooland an replaced with 100% ready to use antifreeze (-26 celsius) costs 2 euros per liter. My 2.0 never orheated, never had the waterpump replaced (140k miles). And the meter always stays just a little pointing down from the middle.

 

I have seen people saying that if mixed it should be done with de-ionized water, true but almost as expensive per liter as antifreeze (well i work in a lab so i can tap real pure H2O by the gallons ).

[OB99W]

I am interested in why would you mix antifreeze with water. As here it gets well below -10 Celcius (14F) and in germany in winters even below -20 (-4F) during the nights. I just flushed my cooland an replaced with 100% ready to use antifreeze (-26 celsius) costs 2 euros per liter. My 2.0 never orheated, never had the waterpump replaced (140k miles). And the meter always stays just a little pointing down from the middle.

 

I have seen people saying that if mixed it should be done with de-ionized water, true but almost as expensive per liter as antifreeze (well i work in a lab so i can tap real pure H2O by the gallons ).

The "100% ready to use antifreeze" you refer to is apparently about 40% antifreeze and 60% water, based on freeze protection to "(-26 celsius)". When you buy antifreeze that isn't premixed, it is 100% antifreeze, and therefore is usually diluted with an equal amount of water to obtain a 50/50 mixture.

 

Yes, it's good to use de-ionized water, and probably better to use distilled; ordinary tap water in many areas is "hard", and disolved minerals (mainly calcium compounds) will come out of solution and form deposits that can at least partially clog passages and compromise heat transfer.

[bratman2]

The 50/50 on the bottle is a catch all that is universally acceptable in all but extreme conditions. An automotive cooling system will generally transfer more heat with more water so boiling point becomes a mute point. EA81 engines used in aircraft were air flow across the radiator may be restricted do run as low as 20% antifreeze to control heat but they change it yearly and this is only in warmer climates. Some automotive manufacters allow lower ratios and still validate your warrenty. For example Ford allows as little as 30% antifreeze according to the owners manual of the 2000 F150 I use to own. My Honda Shadow 1100 recommends no lower than 40%.

 

I would have to check the book on my wifes Legacy to know if that is true with them but I have been running 40% in my Brat for years and changing it to 33% on the next change. Which is what I ran in the F150 after the first change. Don't read to much into the 50/50 mix as that is not always what is best, just universally accepted.

[nipper]

Interesting....did the guy say who recommended to him that he run that mixture?

 

Fact: Water is able to transfer more heat than antifreeze.

 

Here's the thing about antifreeze that most people forget: It does a whole lot more than prevent freezing of the coolant mixture. Among other things, antifreeze has additives that lubricate the water pump, prevent foaming and that type of cavitation (there are other kinds...ask a diesel mechanic), prevent deposits from forming in the engine, prevent corrosion, and keep the pH pretty close to neutral.

 

If you were to reduce the mixture in your Soob, you're taking the chance that the water pump might wear out faster, that more corrosion will happen, that cavitation may happen, that the pH might go acidic, and that more deposits will form. Maybe none of that will occur, but the thing is that you don't know.

 

The first thing that comes to mind when you said that it's a Porsche club is that MAYBE, due to cooling system design and how they're driving, those guys NEED the extra heat transfer ability afforded by the weaker mixture, and they're willing to sacrifice the other things that antifreeze does. Depending on how old their cars are, maybe they were designed to run a 20% mixture. Of course, if they change their coolant more often, then the additive levels would probably be high enough that no problems would develop, but that's all guessing on my part.

 

How cold does it get where you live? How about any place that you might consider driving to? You'd have to double check, but I would venture a guess that a 20% mixture would freeze somewhere around 0 degrees F. If it gets that cold, your engine is most likely going to have a cracked block, which can really ruin your day.

 

Up here, it usually gets to around 20 below duing january, but I also sometimes drive up north where temps can reach 50 below or colder. Taking that into account, I mix the antifreeze in my cars at 75%, which supposedly brings the freeze point down around -60 or -65. Many people don't know that beyond that, a stronger mixture will actually freeze at warmer temperatures. Straight antifreeze freezes somewhere around zero if I remember correctly. Now, I know that I'm sacrificing some cooling capacity in order to prevent a freeze. However, I've never had overheating issues or even gotten my car above the normal temperature range, even in 80 degree weather with heavy loads. Maybe up over 90 degrees, some problems would develop, but I've never been there. So, I'm pretty sure that you've got plenty of cooling capacity if you run the standard 50% mixture.

 

Wow, that was a lot longer than I had initially planned.

 

I would also mention, while we're on the subject, that in my experience, the vast majority of cars on the road today have badly neglected cooling systems. If you change your coolant every couple of years and all the hoses every 4 or 5, your car will thank you for it. I won't get started on SCA's or coolant filters.

 

what he said

 

nipper

[nipper]

I run 50-50 here in SF just like it says on the jug of anti-freeze, no real challenge for heating or cooling here. I don't even bother to test it because it would take an earthquake to get me somewhere it would freeze.

 

waiting for the "big one" to move to alaska eh cookie?

 

nipper

[OB99W]

The 50/50 on the bottle is a catch all that is universally acceptable in all but extreme conditions. An automotive cooling system will generally transfer more heat with more water so boiling point becomes a mute point. EA81 engines used in aircraft were air flow across the radiator may be restricted do run as low as 20% antifreeze to control heat but they change it yearly and this is only in warmer climates. Some automotive manufacters allow lower ratios and still validate your warrenty. For example Ford allows as little as 30% antifreeze according to the owners manual of the 2000 F150 I use to own. My Honda Shadow 1100 recommends no lower than 40%.

 

I would have to check the book on my wifes Legacy to know if that is true with them but I have been running 40% in my Brat for years and changing it to 33% on the next change. Which is what I ran in the F150 after the first change. Don't read to much into the 50/50 mix as that is not always what is best, just universally accepted.

Subaru specifies a 50/50 mix. That not only ensures sufficient freeze-point protection, but also that anti-corrosion and lubrication levels are adequate as well, as has been mentioned. Unless you're willing to monitor pH, etc. of the coolant and adjust additive levels, keeping a 50/50 mix is prudent, simple, and especially if your Subaru is under warranty, meets the requirement.

 

It's true that a 50/50 antifreeze (ethylene glycol) mix has only about 85% of the heat transfer capacity of pure water. However, given that using pure water really isn't an acceptable option, that fact that the boiling point is elevated about 12 degrees F in a 50/50 mix is not moot.

[cookie]

As for moving to Alaska Nip, as far as I'd go would be Tahoe...

I think 50-50 also gives me the lube and anticorrosives I want in there but that reminds me I should check out those hoses before winter. Sure is a lot easier to change them in the current warm weather here.

The fact that if you add too much antifreeze you actually lose freezing point is why we alsys used a hydrometer. At five bucks or so they are much cheaper than frozen engine blocks.

[nipper]

As for moving to Alaska Nip, as far as I'd go would be Tahoe...

I think 50-50 also gives me the lube and anticorrosives I want in there but that reminds me I should check out those hoses before winter. Sure is a lot easier to change them in the current warm weather here.

The fact that if you add too much antifreeze you actually lose freezing point is why we alsys used a hydrometer. At five bucks or so they are much cheaper than frozen engine blocks.

 

actually too much antifreeze, you start lowering the boiling point, and the freeze point gets much lower (colder). ALso since it is less then an ideal system, 50/50 wil give you +/- 10% (60/40) since no one uses a measuring cup

 

nipper