voltage in radiator coolant

[AECS]

Can some of the smarter chemist types around here explain why the voltage is higher (over 1V) at operating temperature then when cold (.05v)?

 

[doghead]

From one of the links I posted,

Always change the coolant if a current is detected. The electrical current will destroy the protecting chemicals in a properly inhibited coolant.

 

[AECS]

Is it better to use distilled or de-ionized water?

 

[doghead]

You can buy pre mixed 50/50.

 

[Mike929]

Is it better to use distilled or de-ionized water?

Use distilled (i.e., no minerals in the water) or buy the 50/50 premix stuff as suggested.

 

[doghead]

Use distilled (i.e., no minerals in the water.)

http://www.distilleddeionizedwater.com/deionized-water-vs-distilled-water/

 

[Mike929]

http://www.distilleddeionizedwater.com/deionized-water-vs-distilled-water/

So you are saying that distilled water is bad to use for coolant? (wonder what the TM says. )

BTW, your link lists "DI water is as pure as the distilled water or even purer", but I'm guessing that the difference, IF ANY would not be detectable in a military trucks radiator.

 

[doghead]

I did not say it.

 

[AECS]

Mixing yourself is 9$ a gallon. Pre mixed is 15...

 

[Mike929]

I did not say it.

I must be imagining things.

 

[doghead]

Spend the extra 25 dollars and know your good.

 

[Keith_J]

Can some of the smarter chemist types around here explain why the voltage is higher (over 1V) at operating temperature then when cold (.05v)?

Heat increases ionization for most liquids and solids, only exceptions would be metals with positive temperature coefficients of resistance and dissolved ionic gases like carbon dioxide in water (carbonic acid) but only because increasing temperature reduces solubility of carbon dioxide in water.

On the water choice between distilled and deionized water here, either is fine. Distilled water can have dissolved carbon dioxide which will boil out on first cycle. Reverse osmosis water is also good. Do not use softened water as it has added ionic content of sodium or potassium.

 

[trukhead]

Can some of the smarter chemist types around here explain why the voltage is higher (over 1V) at operating temperature then when cold (.05v)?

Heat increases ionization for most liquids and solids, only exceptions would be metals with positive temperature coefficients of resistance and dissolved ionic gases like carbon dioxide in water (carbonic acid) but only because increasing temperature reduces solubility of carbon dioxide in water.

On the water choice between distilled and deionized water here, either is fine. Distilled water can have dissolved carbon dioxide which will boil out on first cycle. Reverse osmosis water is also good. Do not use softened water as it has added ionic content of sodium or potassium.

Perhaps the reason for the increased voltage is due to the increased ionization of the coolant with the temperature increase due to the operating temperature of the engine as you operate the vehicle.

Properly charged batteries with maintained correct specific gravity of the electrolyte have less punch to start the vehicle than summer warmed batteries, probably for this reason

I just enjoy this site for the education I continually receive!!.

 

[AECS]

I have been schooled! Thanks Keith_J. That makes perfect sense. Years ago I taught basic aircraft electricians course in the navy, and now I am putting it all together, Aluminum does have that positve temp coeffeciant, which is why it is use allong with Chromele in thermocouples....

 

[AECS]

In all my reading on this I came across a couple of widely varying opinions on the issue of grounding the radiator and heater core. There is a Ford tech bulletin that addresses the issue of electrolysis in the cooling system, it is very specific to NOT ground the radiator or the radiator.

Saw it on a Corvette forum and the discussion had a very good point. As long as they are isolated from ground it is like a battery that is not connected to anything. There is a difference of potential, but since there is not a complete circuit. As soon as a ground is introduced it completes the circuit and electrons flow and corrosion or the loss off the anode (aluminum) occurs.

So I will be doing a coolant swap and removing the ground from the radiator. I will let you all know if I have a whole in the radiator in a week.

 

[o1951]

I recently had my radiator (original) rebuilt because the electrolysis between the coolant and the lead in the joint solder caused it to effectively fill up with mineral deposits after it sat in storage for so long. It was so full of crap, I'm surprised it flowed at all. You could see the white crystals coming through the solder in the corners on the outside of the radiator such that if it were dipped and the deposits dissolved, it would have leaked like a sieve. This is an issue with our trucks that I think is underappreciated, especially with the lower mileage units like mine that sat in storage for a long time. I went through and replaced or rebuilt everything cooling system related at a not-insignificant expense.

That was common in the days of yore, when engines were iron and radiators copper with lead seams. Dupont used to sell (maybe still does) a 2 part cooling system cleaner. Part 1 was powdered oxalic acid, which dissolved the lead crystals. Part 2 was a neutralizer. I did many a cooling system. The cleaner would make everything bright and shiny - cleans up rust too. Woe be unto anyone who forgot to add the neutralizer.

 

[AECS]

Well I give up. I am still getting .5 volts. I have cleaned every underhood ground bright and shiny. I have flushed the coolant till it is clean and clear with distilled water and refiled with new Anti-Freeze (Peak) at a 50/50 mixture.

Still get .5 volts even with batteries both disconnected. I may take it to a radiator shop and see if they have any ideas, otherwise I am going to keep anti-corrosion additive in it, order an anode cap and let it ride till it fails then buy a copper radiator. I have never been beat before, but now I am beat...

 

[MarcusOReallyus]

Hmmm. A long shot, but maybe try disconnecting your heater core. Just bypass it completely, and see what you get.

 

[o1951]

I have had cooling system corrosion failures in more than one vehicle when using the brand you mentioned. I do not trust that brand.

 

[Keith_J]

Yes, you will always have voltage with dissimilar metals connected by electrolyte, this is potential current. Actual current is corrosion rate, one ampere per second is the flow of 6.241 x 10e18 electrons. So measure the current between the aluminum radiator and the chassis ground, this will show corrosion rate. It should be less than 100 micro ampere, if not you need to flush and clean the cooling system.

Aluminum has a molecular weight of around 27, it is trivalent so it loses three electrons in oxidation. So every 27 grams of aluminum oxidizing causes movement of 1.8 E24 electrons, this is Avogadro's Number multiplied by three. If that happened in one second, it would be 289,000 amperes . Over a day, oxidation of 27 grams of aluminum would generate a bit over 3 amps of current. Over 20 years, it would be half a micro ampere.