Propylene Glycol vs. Ethylene Glycol/water 3

[curtis74]

I'm trying to do some math, but would settle for some real-world simplicity since engines don't run on math.

I'm trying to verify some empirical claims from a well-known coolant manufacturer that sells non-aqueous propylene glycol coolant. I'm thinking about using it in my own personal tow vehicle (a 99 E350 Powerstroke) but I'm a bit concerned.

Is the higher boiling point of greater benefit than the loss of the heat capacity associated with not having water mixed with it? I'm hoping to open a dialogue of the benefits/drawbacks based on safe engine alloy temperatures, engine oil temperatures, and hopefully emerge with a better understanding of whether or not I should use the stuff.

 

[MacGyverS2000]

Neglecting random oxygen and hydrogen molecules, "pure water" seems reasonable enough to me... it means no impurities (minerals and such).

It'll suck the ionic snot out of your copper or stainless tubing you try to keep it in, though, and won't stay "pure" for long...

Dan - Owner

http://www.Hi-TecDesigns.com

 

[patprimmer]

To be really pure I guess you need to distil it in glass under a pure inert non soluble atmosphere. I guess pure is an objective term mostly used in a subjective way.

Regards
Pat
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[Metalguy]

That's why I put it in quotes.

"You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is there is no cat." A. Einstein

 

[rmw]

I guess I set this thread off on a tangent. I should have said 'plain' water - meaning water only with, of course requisite treatments and protections.

Freaking water has been the bane of my existence lately. But... that is another thread.

rmw

 

[patprimmer]

Well plain water as in tap water can be a soup of considerably variable recipe. and considerably variable corrosion potential.



Regards
Pat
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[Metalguy]

USA water is generally softer than European water, and hard water plus phosphates are a no-no. Phosphates cause the water hardness elements, calcium and magnesium, to precipitate out--in solid form. Phosphates plus soft water, especially distilled, get along great.

So, while the European manufacturers hate phosphates, the Japanese hate silicates. Both silicates and phosphates protect metals very well, with silicates being especially good for aluminum. Two problems; silicates don't last a long time, and they can be hard on water pump seals--thus the Japanese dislike of them.

"You see, wire telegraph is like a very long cat. You pull his tail in New York and his head is meowing in Los Angeles. Do you understand this? Radio operates the same way: You send signals here, they receive them there. The only difference is there is no cat." A. Einstein

 

[rmw]

Metalguy,

A star for you. When I said a couple of posts back that water was the bane of my existence of late, I meant it. Your last post gave me the information and direction I needed and checking into what you said has revealed the underlying issue. It was not automotive, but what the hay, I guess it is OK to get industrial help from an automotive forum isn't it?

And, funny, I have long since known that - that phosphates precipitate out hardness salts because that is how boiler water treatment works to get those impurities out of BFW so they can be blown down from the boiler, but I never thought about that reaction as regards a fresh (cooling tower makeup) water situation. In our case the phosphates present did a number on the Ca and Mg present and worked against us and plugged a Hx.

Thanks again for the post.

rmw

 

[140Airpower]

Running an engine on PG at 300F or higher is not very radical after all insofar as clearances, oil temps, etc are concerned. This is in the moderate to low range for air cooled engines under load. I think it might call for some redesign of the coolant jacket compared to water. You might want some short fins inside the jacket to improve heat transfer from certain areas like exhaust seats and combustion chamber tops. The lower portion of cylinders should not need coolant jacketing. An oil cooler would be mandatory as the oil will need to run cooler than the jacketed parts of the engine and will establish the temps in the crankcase and everywhere not jacketed. All the other issues discussed would need to be worked out.
I like PG a lot for its low-toxic nature.