Distilled water in question

[Mayhem_J30]

After replacing a radiator on the I30 last night I got thinking...

It seems distilled water can be very corrosive to aluminum. The very metal are radiators and engine blocks(depending on engine model) are constructed from. So you sacrificing mineral deposits for another mess. Just as any google search with "aluminum + distilled water" will turn up results about not mixing aluminum with distilled water to be drinking water. Apparently the water is stripping the aluminum from itself.I question what antifreeze manufacturers plan on the consumer using. We know that antifreeze will generally have some sort of acid neutralizer to keep corrosion to a minimum, but can it combat the distilled water looking for those aluminum ions? I'm not a chemist so I don't know. Maybe Redline water wetter is the answer...

But if this IS true it would make sense to always premix your coolant solution before introducing it to your coolant system. YOu wouldn't want pure distilled water in contact with your aluminum radiator without the antifreeze neutralizing the reaction(assuming antifreeze can handle this). I'm waiting on a email response from Prestone now to see what there additives are designed for.

Can anyone enlighten me some more on this?

[maxnix]

Distilled water Ph = 7.0. Neutral. Better than basic (Ph > 7.0) which will leave deposits, or acidic (Ph < 7.0) which will attack the aluminum and bring it into solution.

[VimyJ]

It would probably take weeks for distilled H2O to have an effect on the AL.

[Q45tech]

"The alkalinity of an antifreeze/water mix varies because of the additives used and the ingredient ratio but should be between the pH range of 8 and 11. The average antifreeze pH value is 10.5. When the antifreeze is mixed with water and added to the cooling system, the pH decreases to 8.5 to 9. A higher pH level is not always better because some new long-lasting coolants have a pH of 8.3. As long as the pH value stays stable, the cooling system is fine."

Long life coolants have a lower INITIAL PH [8.3] and stay stable thus less shocking to aluminum when installed or changed.

What is added to drinking water in most locations will drive you to drink nothing but distilled water.

Doesn't really matter since you are changing [some of] the coolant every year anyway are you not? Simple rad drain and refill even with dexcool to adjust your mixture for summer winter with Redline wetter water........50% winter 35-28% summer.

The factory fill is distilled/deionized [as far As I can tell for all vehicle manufacturers around the world.No dealers use anything but tap water.........same with the water added to batteries by tech.

The phone companies who require 20 year battery life use only distilled water.

If you check the PH at every oil change and correct there is no reason hard systems should not last forever..........hoses fail from oxygen exposure.

[elwesso]

I liked that thing, Dennis, where you can put a multimeter probe into the radiator and determine if the coolant is decent or not..

What was that again (without searching)

[Mayhem_J30]

I liked that thing, Dennis, where you can put a multimeter probe into the radiator and determine if the coolant is decent or not..

What was that again (without searching)

I believe it has something to do with the conductivity of water. The more acidic it is the better it conducts electricity. Putting a volt meter and measure the mV between an engine ground and the water in the radiator. If you start to get measurements over 300mV it's too acidic and time for a flush.

[PalmerWMD]

Distilled water has no buffering system, wether designed ( as in coolant), or just due to mineral contaminats, which buffer a bit .

Also ,it has a higher solvency for metal ions, due to its extremly low ionic strenght (by definition near zero prior to teh uptake of CO2)

Also, its easily pics up CO2 from air, to form carbonic Acid in solution.

But none of this matters, the instant it is mixed with the buffering sytem present in coolant and also completly changes the ionic strenght and reduces the uptake of CO2 from air.

In summary: Dont worry about ,it continue to mix as we recommend 50 /50 winter 70 distilled/30 coolant summer.feel free to add a bottle or RWW in summer the volume for this can come from the coolant.

Example in a Q45 Just under 7 quarts distilled water, one bottle RWW rest Coolant, for a mix of approx 70% distilled water, 3 % RWW and 27 % coolant mix

Fred...

[AZhitman]

Look who's been studying.

You guys make my head hurt sometimes - good info!

[texasoil]

Distilled water or deionized water are certainly OK, and much bettter than most tap water to mix with antifreeze solution. They should not be used without at least 30% antifreeze as there will not be sufficient corrosion protection.

The problem with some tap waters is the chlorine content-- which is not good for cooling systems. Also, some tap waters have a lot of calcium and magnesiun (hardness) which can plate out on the radiator tubes.

'Soft" water can be very corrosive unless mixed with antifreeze.

[Q45tech]

Actually with carboxyl acid type additives as long as the blended PH exceeds 7.4.........you can get away with less than 30% but as I said you must change the coolant or reinforce [the bump up....the 2 quarts of 100% you add as the temp drops in EVERY October.

Examining [and weighting] the corrosion inside the metallic junction pipe [rad output/feed to thermostat ] will tell you whether the corrosion is excessive.

Unless you know what you are doing and make [ph/ionic conduvctivity] measurements probably best to just stick with 50/50 changed often.

[Q45tech]

http://www.eetcorp.com/corpora...t.pdfh ... dex.htm"Dr. Carr goes on to show that, in conventional coolants, diluting the coolant 9-to-1 with distilled water does generate a more reliable field test to estimate the concentration of total dissolved solids in the coolant. To make this method work, Dr. Carr's curves in the paper need to be used. Amalgatech has generated a similar set of data by repeating the experiments, graphed above.

Amalgatech further refined this approach by developing a curve for dilutions of coolant made in a ratio of 49-to-1. Amalgatech found that this dilution effectively eliminates the effect of glycols in the coolant, and predicts the actual TDS (total dissolved solids) concentration of the coolant. Because the dilution must be precise, this is probably a laboratory method.

Conductivity estimates of TDS in coolants is limited to conventional coolant technologies.

[PalmerWMD]

Unless you know what you are doing and make [ph/ionic conduvctivity] measurements probably best to just stick with 50/50 changed often.

I respectfully disagree Sir.

In summer 70 dist wtr/30 coolant with reasonable change intervals IMO.

The reserves built into a 50/50 mix (at the expense of heat capacity/flow) are there to protect the typical owner from himself and a likely lack of changing for years, perhaps several years.

A 70/30 in summer or in warm climates, year around, will add a reserve in heatcapacity that otherwise wouldnt be there.

As long as a reasonble change interval is maintained, this is the superior (and time tested) approach IMO.

Fred...