overheating while idle

[Bambikiller240]

Originally posted by Daniel

My point is that antifreeze is not any kind of shield (to heat), it does not keep "hot" from metal---**EDIT Actually in that antifreeze/water mix is less efficient at removing heat, it is a shield;----- Why Gee Carl you've covered all the bases tonite huh???? (sorry i couldn't help it):stupid:

Daniel:

I got caught up in the discussion :stupid: , as to the shielding properties ( the "antifreeze" form a protective sleeve in your engine to keep the hot from the metal") seemed to be touted as beneficial, or a reason for antifreeze to be used; rather than something to be "lived with" to gain the other benefits of ethylene glycol.

I live in Northern CA and while we don't get snow in my area, we do regularly see freezing tempuratures as early as November and as late as April. We also regularly see tempuratures in the 90 to 105 degree F. range as early as late May and as late as Mid October.

I have been using about 20% antifreeze, 80% water, and Red Line Water Wetter in the winter, and water only with Water Wetter in the summer for the past 3 years. My engine stays remarkably cool in the summer (I have added a fan shroud to improve airflow through the radiator in summer time stop and go traffic) and never have experienced problems with freezing in the winter. The Water Wetter has an anticorrosive package in it so that base is covered when there is no antifreeze in my car.

The best part of this thread is the information that you, mdbrandy, and myself have spelled out for other members to learn from.

[Bambikiller240]

Originally posted by Brett240

please avoid using tap water.

again no offence meant.

No worries mate!

But, Why don't you copy your post on this subject to the Tech Article thread so that this information will be viewable to others who read the one that I posted there? I only moderate that one forum, otherwise I'd copy it there myself. ( I can delete or move stuff OUT, but I can't move stuff INTO that forum)

[Brett240]

done!

[mdbrandy]

I give up. Nowhere can I find the freezing point of pure ethylene glycol. Even the handbook of Chemistry and Physics only lists the freezing point depression to 60% glycol. The only thing I did find was a very bad chart that indicates that the freezing point decreases to 67% and then rises again, which supports Daniel's contention. I stand corrected. The (very, very poor) graph is attached. The graph on the left seems to show the freezing point on the bottom curve, and the boiling point on the top curve as a function of the % glycol. Note that the article that I got this from was comparing ethylene and propylene glycol, and I think the left curve is ethylene, and the right two propylene.

Anyway...

[Bambikiller240]

Originally posted by mdbrandy

.........The only thing I did find was a very bad chart that indicates that the freezing point decreases to 67% and then rises again, which supports Daniel's contention. I stand corrected. Anyway...

The supported contention was that a mixture of water and antifreeze is more efficient than straight antifreeze, right?

But (if I'm reading the charts and you correct) this doesn't relate to whether antifreeze/water mix is more efficient at thermal transfer than straight water, right? This I believe to be different from how much heat antifreeze/water mix an hold without boiling.

I'm definitely not a scientist, and definitely not trying to start an argument or be critical here, just trying to make sure that I understand. If I'm wrong on these statements, please try to clarify. Thanks.

[mdbrandy]

Daniel had stated that a 100% fill of antifreeze would freeze before a 50/50 mixture, and I had a hard time believing it. From the graph I found, and from the fact that several different antifreeze manufacturers state that they do not suggest more than 67% antifreeze, I conclude that he is right.

[Bambikiller240]

Originally posted by mdbrandy

Daniel had stated that a 100% fill of antifreeze would freeze before a 50/50 mixture, and I had a hard time believing it. From the graph I found, and from the fact that several different antifreeze manufacturers state that they do not suggest more than 67% antifreeze, I conclude that he is right.

OK, Mark. Got it! Thanks

[Brett240]

refering to my original post,

id say the manufacture stating no more than 67% would have more to do with the mixtures ability to transfer heat decreases as the additive percentage increases, and the resulting engine temp issues.

(which, and im not neccessarily right on this point, would not show up on the tepm gauge as the gauge only shows water temp and not the temp of the engine)

[Bambikiller240]

Originally posted by Brett240

refering to my original post,

id say the manufacture stating no more than 67% would have more to do with the mixtures ability to transfer heat decreases as the additive percentage increases, and the resulting engine temp issues.

(which, and im not neccessarily right on this point, would not show up on the tepm gauge as the gauge only shows water temp and not the temp of the engine)

Makes sense to me.

[Daniel]

As promised this is a paste from the Peak antifreeze webpage. Water is an excellent conductor of heat. Glycols are not as good of heat conductors as water. As the concentration of glycol increases, the heat transfer ability of the mixture decreases. This change in heat transfer is not a problem. During engine and cooling system design the heat transfer ability of the coolant is taken into effect. What is important is not using a fluid that is outside the cooling system design parameters. Modern engines are designed to run with a glycol - water blend between 40% and 60% glycol. Using a coolant outside these limits will cause the engine to run at the wrong temperature. This change sacrifices engine performance and leads to other problems.

The second function of an antifreeze is to protect the metals in a vehicle's cooling system from corrosion. Antifreeze is able to perform this function by the addition of inhibitors. Inhibitor types vary depending on the type of antifreeze. Inhibitors can be of many different forms including organic and inorganic chemicals. One thing that is common with all inhibitors is that they are designed to work in a water solution. The addition of water "activates" the inhibitors, allowing them to protect the metals. For this reason it is important to always mix antifreeze with water in a vehicle’s cooling system.

As the name implies the third main function of antifreeze is to protect the cooling system from freezing. The way to achieve maximum freeze protection differs between ethylene and propylene glycol. For ethylene glycol the maximum protection is at 67% ethylene glycol in water. A ethylene glycol solution of this concentration will freeze at -84° F (pure ethylene glycol freezes at 8° F). Propylene glycol does not freeze. It experiences a chemical phenomenon known as supercooling. For this reason there is no freezing point of pure PG. Due to the heat transfer and inhibitor activation reasons discussed above, PG antifreeze should also be maintained between 40% and 70% in water. Boil over protection with both glycols increases with glycol concentration.

[mdbrandy]

Originally posted by Daniel

For ethylene glycol the maximum protection is at 67% ethylene glycol in water. A ethylene glycol solution of this concentration will freeze at -84° F (pure ethylene glycol freezes at 8° F).

That data matches well with the graph I posted. So I guess it was the right graph! The quotation Daniel posted from Peak seems to synopsize most of our discussions well.

Thanks!

[seerex]

if you are gonna rebuild your fan clutch check out this post I found very helpful , good luck Jeff:geek: http://www.classiczcars.com/forums/showthread.php?s=&threadid=10401