Distilled Water for Radiators as Coolant

Yes, the ph of distilled water is neutral....no negative effects....Your water should be mixed with coolant additive as per manufacturers recommendation....

I'm adding this as a clarification...Freshly distilled water should have a pH of 7.0. However, interaction with the atmosphere allows carbon dioxide to dissolve into it, forming carbonic acid. As a result, agitating the water or allowing it to sit for a while will leave you with an aqueous solution that drifts down into the acidic range, however mixing a suitable coolant should keep this from being a problem....I would test the ph of the final mixture to be safe, and if acidic, add a coolant conditioner to prevent corrosion....

Why? It won't be classed as distilled once the additives are introduced!

Water is a polar molecule, and thus will try to bond with any available materials it contacts. Mixing in dissolved minerals like those found in antifreeze mixtures (commonly glycols) can actually increase the heat transfer properties of the water mixture.

Drew K

So, in what way is the water distilled if the additive has dissolvable minerals in it?

The concept is now meaningless.

Not sure, perhaps distilled water will dissolve and mix better with the anti-freeze additive?

Perhaps if your water was supersaturated with mineral you would get deposits as the anti-freeze displaced the minerals? So far though, I have not had water in my house so hard that it does not dissolve table salt or sugar...so I will continue to use tap water (unless I see good evidence here).

Drew K

I would be hesitant to use only distilled water in an automotive cooling radiator system because of the anti-corrosion, seal lubrication and prevention of freezing that anti-freeze and its additives provide. You certainly can top-off an existing system with distilled water. Pure distilled water can also be used temporarily for the corrosion process will be a gradual decay.

Without knowing all of the parts of your cooling system or even if this is an automotive cooling system, any answer will be just a blind guess. I say go for it! You're not working on my car.

Add some Redline "Water-Wetter"....

coolant is formulated to reduce electrolysis between unlike metals as well as moving more latent heat, to the the radiator, e-g.

Shiraz,

Your question seems to have been answered pretty well here.

Back at you now....

Why do you ask?

Corrosion is not the main problem. Distilled water has a boiling point of 212 F and a freezing point of 32 F. A 50/50 water/glycol mix boils at 223 F and freezes at -35 F. (Note: the car's cooling system is normally pressurized about 15 psi, so the boiling points in the radiator are higher.)

Using water instead of water/glycol is asking for boil-overs and frozen blocks.

There is an ancient British Railways formula for radiator water. This prevents corrosion even after years of use.We have been using this in many cooling water applications not only in radiators.

Potassium Dichromate - 230 gms

Sodium Nitrate - 50 gms

Sodium Carbonate - 60 gms

Borax to buffer pH to 8.5 Approximately 40 gms

Water 60 litres

If this is to be used at room temperature add 200 mg Copper Sulphate as bactericide and fungicide.

CAUTION: Not for food contact.

You might want to reconsider the dichromate. You will get Cr+6 ions which are considered a pretty strong cancer causing agent. Many countries would consider this a very hazardous mix if you put the dichromate in it.

Distilled water is the purest form of water which can be used as a coolant for Radiator as the material of radiator is copper which will be protected.In Lead acid batteries we recommend distilled water to be added in the acid columns.

R.Sethuraman

What about the cast iron or cast alloy materials of the engine block?

And of what relevance is the lead-acid battery herring?

Normal, Standard non distilled water contains Dissolved solids of different elements: Calcium, Sodium Magnesium etc in different concentrations. These will tend to precipitate and deposit on hot surfaces. They are the cause of radiator and engine block passages getting blocked... this is apart from the corrosions due to the presence of, mainly, dissolved Oxygen in the water.

Using distilled water will 1st eliminate most of the dissolved solids, thus reducing the blocking by deposits formation. This is good at first consideration.

BUT, the Oxygen is still there, in the water, due to being exposed to the atmosphere. To remove the Oxygen, you might boil the water for some time, before introducing it into the radiator! This is called degassification. You will need to introdue it while still very hot! in this way, you have a good coolant and prevent corrosion.

The problem will come later, when topping the water with fresh water, even distilled, when new oxygen is introduced.

Therefore, it is better to include an anti-corrosion additive that is an Oxygen scavenger. this will be dosed as to have enough residual scavenging potential to cater for any topping in the future. (Untill you add some more).

If anti-freeze is included in the commercial additives available, then fine otherwise you only need it (as a separate additive) if you are in a region where freezing temperatures can occur.Heat transfer efficiency is best with water alone. Aniti freeze will reduce this efficiency a little, but acceptable to prevent freezing.

The presence of dissolved Oxygen will corrode all metals, particularly where the temperature is highest: Cylinder wall, water side.

I am not trying to be argumentative or question your...just I am not convinced...can you provide research or data to back up your comments?

I don't see how you can prevent such a strong polar molecule from trying to tear apart any other polar molecule or attract free atoms. I don't know for certain and have read (today) many arguments back and forth but not much real evidence. I do think that the radiator coolant and car manufacturers have done lots of research...I just don't have time to find it right now...because I am going out to get a few bottles of my favorite seasonal ale!

Drew K

Get an extra 6-pack, I'm coming over.

I bought my first vehicle in 1964. Used well water AND 50% antifreeze in it. The farm truck, a 1950 GMC, used the same water antifreeze mix.

Now I use bottled water and 50% anti-freeze and change it every 3-5 years. OK, the shop now does the work.

I've never paid the slightest bit of attention to disolved O².

I HAVE NEVER had a corrosion problem in any of the vehicles I have owned.

Cheers!

Well, when you get your hands on the info I would like to see it. It will add to our education and thanks.

Now, which part of my comments needs to be looked at?

I do not pretend to be the only opinion here (and you have a lot of them...) or to be dogmatic. I only expressed what is really known on the subject. My experience on this matter is what is being expressed here.

Consider the following: If you use a tap water or any untreated water for that, after a period of time, what ever it contains will either remain dissolved in the water or deposits on the internal surfaces. Once this has happened, there will be a balance and no more reaction or deposits. the media will be in equilibrium.

What is the real problem? In my opinion, if no water is added ever as a topping, nothing further should be happening. BUT unfortunately, depending on the circumstances and the maintenance done to the vehicule, some topping is done all the time, with different frequencies which depend on the OVERHEATING history or Other factors. THESE additions bring the extra dissolved solids that will keep increasing the deposits until blockage of some sort or making the heat transfer worse.Therefore, every individual can claim his experience with his own vehicule gave him a different result ( I used just any water or did not worry about it etc or I am having a problem ...)

Dissolved O2: yes this is very well documented in all water treatment documentations that deal with the subject. You can easily accept that CO2 is dissolved in water but wonder about O2?

The main corrosif element in water is the O2 and all respectful anti-corrosion additives will deal with it particularly.

Please let me know which aspect of my previous submit did not go well.

By the way, so as not to forget: Distilled water will try to deplete some of the metals available in the circuit as you have said, but tel me in what form does it do that? Are you saying that Iron or Aluminium dissolves just as atoms, like sugar in water? or these are attacked by the H2O and we have some free radicals in solution like MO-, H+ in general? In any case, there will be an equilibrium, and unless there is a leak or loss of liquid to be replaced all the time, no more corrosion will take place.

Any constructive info or explanation is wellcome.

In addition to my response to Drew, let me say this. I was engineering manager for a wet process equipment company for 5 years, 15 years ago.

We built fresh water and DI water rinse systems as part of our equipment. This equipment was shipped all over the world.This water was all delivered via spray bars and pumps. It was highly aerated by this process.

We used brass valves and plastic (mostly) plumbing on the fresh water rinses. When we built DI rinses, ALL metal hardware had to be 316 ss. Nothing else would last more than a week when exposed to DI water.

Lyn, first, there is a difference between Di and distilled Water.

http://en.wikipedia.org/wiki/Distilled%5Fwater

Your experience, as described, will not be the 100% applicable to the cooling system of cars ... or similar heat transfer applications.

Ordinary fresh water will be more stable during rinsing in open air as mentioned, because it contains dissolved elements like calcium carbonate and other which act as buffers to keep the pH stable, and rarely acidic: most probably pH > 7

DI water will easily becaome acidic during the spraying action because it will readily dissolve CO2 from the air and form an acid solution, not much different from your carbonated drinks (Coca Cola ...). .(Rain water absorbs CO2 while coming down and become acidic, dissolving underground rocks .... caves...)

Distilled water in a radiator will not (normally) get CO2 or O2 unless there are leaks or the system is Open to the atmosphere.( in turbo charged engines, if the after cooler is leaking, air will get into the coolant system and increase corrosion...) Now, adding Oxygen Scavenging components means that the pH will increase above 7. For this reason, if Aluminium is present in the circuit, the pH should not be allowed to go too high above 7.5, hence special additives. In Steel (or Iron) circuits, the pH can go higher, up to 10-11.

Anyway, I am only trying to clear some points and there must be some expert professionals in the water chemistry applied to cooling systems for vehicules. There are a lot more parameters involved to consider, but in a general way, distilled water is OK but pH must be corrected with an adequate additive to prevent it becoming acidic...

OK,

I'm fine with what you are saying.

Unfortunately (as is usually the case) the OP chose to give us no useable information, nor any follow-up responses.

Distilled water/radiators/coolant is all the information we have.

I think we are all trying to help someone who DOES NOT deserve any help!

Cheers.

Cheers

You say the main corrosive element in water is the O₂? My local power plant uses sacrificial anodes inside its tube heat exchangers to protect the steel. They use normal water for the cooling tower side (monitored for PH). The water becomes more contaminate dense as it cycles through the cooling tower where water evaporates. When it is determined the water is beyond use, they blow down the tower into a evaporation pond and use fresh water from the treatment system.

I don't know which would cause corrosion faster, an oxygen rich water or a anodic section of the coolant system but I do know what is controlled in the power plant's system.

Drew K

Cooling Tower water in a power plant:

1- The water temperatures reached in such a system will not get to the same level as in a combustion engine cooling circuit. For sure, it might not reach the boiling point under atmospheric pressure, i.e. ~70 to 75°C (?)

2- Since the cooling tower uses ambiant air, more contaminants will be carried into the water, including CO2 and O2 etc whatever is in the AIR.

3- Water evaporation is the process relied on to cool the water. Therefore, it is normal for the water to become more dense with dissolved solids due to the continuous replacement of the evaporated water, by fresh water.

4- The sacrificial anode action has nothing to do with the subject of this discution since I do not think that you would normally find them in the cooling circuit of car engines. However, the usage and modus operandi of such devices has more to do with the electrical potential of the elements or metals used in the heat exchanger ... Valence of the elements. Therefore, the anode is chosen so that it will lose mass due to electrolysis more readily that the metal of the heat exchange. in fact, the metal of the anode will migrate to the heat exchanger metal, thus protecting it: The anode corrodes instead of the heat exchanger.

When you say Corrosion, you say Oxydisation (... O2 involved ???).

I did not get your point in your introducing a cooling tower + Anodic Section (??) etc.. Also, what is it that is controlled in your power plant's system? The pH, the ppm, the anode size, ... temperature, density ... You can control any parameter as long as it is relevant to the objective. What has it got to do with the OP's question or my subit?

Sorry, didn't mean to confuse the issue.

I was responding to where I thought you were talking about corrosion, which is mitigated with a cathode.

Drew K

http://ls1tech.com/forums/general-maintenance-repairs/888251-distilled-water-aluminum-radiator-yes-no.html

http://answers.yahoo.com/question/index?qid=20070521230644AAbCqcE

Distilled not essential but won't hurt either.(?)

This has been well-covered above. I'll add a couple of bits: I personally use rain water. Do not use tap water--ours is particularly bad, but most is not good enough. I have heard it described that distilled water is "hungry" for impurities and thus will corrode your system. Always use a corrosion inhibitor or antifreeze; the latter if you might, maybe, perhaps, have freezing conditions. I think most radiators today are aluminum, not copper. I have a non-sealed cooling system which used plain water for many year while in the warm firehouse, and it has severe cathodic corrosion on the inside of the aluminum components.

As a fluid to transfer heat from the cylinder heads to the radiator, distilled water is better than antifreeze and water. But the additional boiling temperature provided by antifreeze and water may well be needed to prevent the coolant from boiling in today's hotter running engines. GM has used coolant temperature sensors that did not trigger the hot light until 276 degrees. What will pure distilled water boil at under 15 pounds of pressure?

<...What will pure distilled water boil at under 15 pounds of pressure?...>

The same as any other water, including domestic sewage. The answer lies in published Steam Tables.

I owned a 1972 Dodge truck for nearly 30 years. It had no overflow for the radiator. I topped it off with tap water in the summer. For may years I drained the radiator and replaced the fluid with 50% antifreeze and 50% tap water every fall or every 2 years. The last 10 years or so, I never did a flush job. I never put in any chemicals other than antifreeze. It never plugged up. I finally had the radiator replaced after nearly 30 years because it was leaking.

In my opinion, it won't do any good or harm. The purity of the water will become instantly impure as the ph adjusts to the cooling system.

I scanned the responses and find it hard to believe that very little was mentioned as far as what the manufacturers state. I believe they have some engineers who actually work in that arena and may actually know what's best for a vehicle. In virtually all newer cars (20 years or so) the owner's manual states that distilled water should be used.

Why would this even really be a question? If everyone is going to go as far as testing pH for distilled, do they go as far as testing the pH out of their garden hoses?

I think we think too much.

My 2004 Chevy owners manual only says to use clean, drinkable water and 50% Dex-cool.

Go figure.

Yah, so I notice. Chevy probably got smart and realized that people probably didn't have a distilled water source readily available to flush their engines.

I don't think owner's manuals are written for people who know anything about cars.

How many people actually read their owners manual? I read mine only when something goes wrong.

Maybe (and this may be a mental reach for some) if people would actually read things that are put in place for just such a purpose (from time to time) they wouldn't need to resort to the internet and all of its lunacy and witch's brews to answer what is truly a simple question.

But I am sure that is asking too much.

In virtually all newer cars (20 years or so) the owner's manual states that distilled water should be used.

But I bet in combination with an antifreeze to get the corrosion protection, higher temperature before boiling, and, of course, freeze protection.

Well, duh, of course. That's kind of the whole idea.

Unfortunately, the OP said nothing about any fluid but distilled water, leaving one with the impression that distilled water would be the only working fluid in the system.

Garbage in------------------garbage out.

WALOOB

I would assume that you mean adding only distilled water "along with the antifreeze" and not just distilled water by itself. Most modern car thermostats are set well above 212 degrees and are pressurized. The use of glycol antifreeze extends both the boiling point and the freezing point of the coolant beyond that of plain water. Most modern anti-freezes contain inhibitors to protect the metal. If the mix is not kept at 50-50 it can create a problem. When I was young, it was recommended that you use only distilled water to add to your radiator and anti-freeze and it had more to do with the calcium and other minerals found in common tap water which could cause deposits. I doubt that any entrained trace amounts of gases such as CO2 or O2 would remain in the system very long since they would tend to rise to the top of the radiator and blow out the overflow cap before any liquid was expelled.

<...glycol antifreeze extends...the boiling point....>

Nonsense: keeping the system under pressure raises the boiling point.

Not nonsense. Just insignificant. The pressure increase is the major change in boiling temperature.

According to this thread to a glycol manufacturer the freezing point and the boiling point will vary dependent on the relative percentage of glycol vs. water at the same containment pressure which is how I remember it. Granted that just keeping the system under pressure will increase the temperature at which the fluid remains fluid but the mix of the fluid does also affect the boiling point.

http://www.nemco.mb.ca/pds/antifreeze_propglycol50.pdf

BOTH raise the boiling point. I think independently. Antifreeze will raise it, and pressure will raise it some more.