Coolant and Distilled Water

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I've heard several people mention using distilled water to mix with coolant versus tap water.

I want to talk more about this. I agree that hard, mineral saturated water is bad for your cooling system. It can settle out, block small openings and generally gunk stuff up.

But I assert that distilled water is TOO clean. I think you need some level of minerals so that a thin layer of deposit is laid on the walls of passages or you will get pitting and eventual failures where the flow is very turbulant.

I guy I worked with years ago repaired boiler heating systems. He found that this was the case for those hot water systems; you NEED some calcium in there to avoid pitting the pipes.

So my solution (with my relatively soft Chicago Lake Michigan water) is to drain, fill totally with tap water, run up to normal temp, repeat twice (to flush the gunk out), dump pure coolant into the tank (quantity=capacity/2), then top off with distilled water. Because some of my second round flush tap water is still in there, I figure my ratios are about 50% coolant, 30% tap water, 20% distilled.

Never had a cooling system failure.
 
Much of your ground water is not only saturated with calcium
carbonate, but silica too. It frequently is low in iron and drinking
standards call for low copper. Any water you put in your radiator
will quickly become saturated with whatever metals are present in
your engine, iron, copper, aluminum, etc. Once the minute amount
needed for this is dissolved, no more will dissolve until more water
is added. In the meantime if you are losing any water vapor,
whatever solids in the original water will be deposited somewhere in
your cooling system. This leads to scale. So the lower solids
content the water your add, the better. Distilled water is a good
choice. I take my chances with rain water.

As for a boiler needing a little calcium to protect the iron, due to
ionic strength, water with calcium compounds in it will hold more
iron compounds. In a steam boiler, all the salts will stay behind as
scale on the heat exchange surfaces. The condensate is distilled
water except for whatever volatile treatment compounds may be in
it. I have a degree in Chemistry and my experience has included
keeping a small factory with cooling water and steam systems
running.
 
If you are using death-cool, distilled water is required. The extreme high sodium content tends to break apart the other mineral compounds and form strong sodium hydroxide
 
You better believe that pure water pulls metal apart.

At the power station, the boiler feed water is deionised, as labman pointed out to increase the number of cycles through the boiler before we have to blow it down.

We've got some mild steel pipes in the demin water lines that get wrecked by the water.

We use ammonia treatment to get the pH up to a point that it doesn't wreck the plant.

(Local steamtrainers use TSP, but they are low pressure, low temperature, and blow down pretty hard anyway).
 
Well there was a chemical engineer on another forum I visited that always said tap water is best and using distilled is not a good idea. I can't remember why though.
But in my case, I don't think that would apply. We have public well water and it is insanely hard. It is over 33 grains per gallon! Last flush and fill I used tap water, but now I wish I didn't.
You have good water, so I wouldn't worry about it.
But I'm not sure your example applies either, because of the antifreeze in the cooling system. The other application is pure water.

Wish I could find a definitive answer.
 
I have read the ultra-pure water mixed with coolant causing problems....to this I say:

BUNK!!!!!!!!!!!!!!!!!!!!!!!

The theory is that the ultra-pure water will seek and dissolve the first metal it touches.....even if this does make sense, the fact that the ultra-pure water is mixed 50/50 with the coolant always seems to be forgotten.

Jason nailed it - if your water has any above average hardness, just get water with ions/salts removed by a method of your choosing. Since you are spending money for bottled water, best get the lowest amount of non-H20 goodies for the buck. If you are lucky to live in a area with low hardness/solids water use it.

I have tap water/coolant in my cars currently and before and never had an issue, but sometimes I use di/distilled H20 - the water was never an issue.

[ June 20, 2003, 12:47 PM: Message edited by: Pablo ]
 
It's not so much about using distilled water, as it is about using demineralized water. That will prevent mineral deposits suchs as scale.

Usually, the demineralized wayer you can buy happens to be also distilled water.
tongue.gif


If you want to see how much crap is in tap water, fill a glass and let it vaporize. All the suff that's left is what's in there. You'll be surprised what you'll find - depending on the composition of your tap water.

PS: Word of caution: It's not a good idea to drink demineralized water. It will deplete your body of essential minerals, which can be fatal.
 
quote:

Originally posted by manualman:
I've heard several people mention using distilled water to mix with coolant versus tap water.

I want to talk more about this. I agree that hard, mineral saturated water is bad for your cooling system. It can settle out, block small openings and generally gunk stuff up.

But I assert that distilled water is TOO clean. I think you need some level of minerals so that a thin layer of deposit is laid on the walls of passages or you will get pitting and eventual failures where the flow is very turbulant.

I guy I worked with years ago repaired boiler heating systems. He found that this was the case for those hot water systems; you NEED some calcium in there to avoid pitting the pipes.

So my solution (with my relatively soft Chicago Lake Michigan water) is to drain, fill totally with tap water, run up to normal temp, repeat twice (to flush the gunk out), dump pure coolant into the tank (quantity=capacity/2), then top off with distilled water. Because some of my second round flush tap water is still in there, I figure my ratios are about 50% coolant, 30% tap water, 20% distilled.

Never had a cooling system failure.


Bull.

Ok, you never had a cooling system failure, but your reasoning is full of holes.

Distilled water is slightly acidic. A boiler or any other system needs correct water treatment. For a boiler, use boiler water treatment chemicals. For a gasoline engine, use antifreeze/water mix, or another suitable corrosion inhibitor. For a diesel engine, use antifreeze/water + treatment chemicals to prevent cavitation.

Forget about adding calcium salts to the water. That's totally in error. And, minerals in water do not settle out. They may combine chemically with components in the antifreeze and form a precipitate which can clog a radiator.


Mordibundman,
No problem drinking demineralized or distilled water...I've drank gallons during my 35 years of going to sea. The water was all distilled from sea water to sufficient purity for high pressure boilers (0.1 grain/gallon of salt--sea water is about 3.5% salt, and 850 psi boilers), and when we were in hot tropical areas and working in the engine room, all of us drank plenty of water with absolutely no physical problems.


Ken

[ June 21, 2003, 05:40 PM: Message edited by: Ken2 ]
 
It might depend on the coolant you use, too. For all those that have Toyotas and use their red coolant, it states in the manual to use distilled water. I don't know if Toyota Red is specifically designed to be used with distilled but it works great together.

[ June 21, 2003, 08:51 PM: Message edited by: Toy4x4 ]
 
True, distilled water is slightly acidic. However, the acidity goes away once the water is heated for the first time, if I remember 9th grade Chemisty class correctly.
wink.gif

Also, coolant is buffered, so the acidity should easily be neutralized.

VW/Audi strongly recommend using distilled/demineralized water when mixing G-11, G-12, and G-12 Plus coolant.

As for drinking demineralized water, I'm not a doctor, and the supposed danger in drinking it may be due to old wives tales, but do you think it tastes GOOD?
tongue.gif
 
quote:

Originally posted by TheLoneRanger:
Posted by Shannow:
quote:

We use ammonia treatment to get the pH up to a point that it doesn't wreck the plan

What about pouring a few ounces of ammonia in the radiator? Would this do anything beneficial?


TheLoneRanger,
ammonia in contact with copper based alloys is the last thing that you want. It will pull the copper out of your radiator quick smart, and leave you with a brittle, porous mess.

That's why a lot of rifle bore solvents reek of the stuff.
 
Tap water also has chlorine.
something from a ChevronTexaco service presentation:
- Chloride, sulfates, Magnesium, and Calcium produce the formation of deposits, sludge, and corrosion.
- High levels of chlorine attack aluminum.
- Calcium and Magnesium react with fosfates to form deposits.
...
It is best to use:
1. Deionized water when mixing
2. Distilled water
Not tap water

The seriousness of this depends on the type of coolant. If using a tradicional Antifreeze/Coolant, it is super critical. If using one of the carboxylate products (Dex-Cool, Delo Coolant) it is less important but it gives limits of the above contaminates per gallon.
When you get the pre-diluted version it comes with Deionized water.
 
I have always mixed tap water with my coolant, and never had a problem. Then again, I change the coolant in my vehicles every 30,000 miles. -Joe
 
So Chevron also recommends deionized (= demineralized), distilled water? That confirms that what I've been doing for many years was right.
cool.gif


I don't know the chemical composition of the coolant VW/Audi use, but it is phosphate-free and it doesn't mix with any other over-the-counter coolant. In fact, G12 and G12 Plus don't even mix with the older G11.
 
Anyone know what the factories use? Detroit city water is relatively low mineral river water. I also believe much of Michagan doesn't have the extreamely hard well water as many other places. Are the manfacturers paying for deionizeed water? Unless you are continually having to add more, I doubt fairly low mineral tap water is a problem.

I don't think I have added anything to my car in the year and a half since I bought it, or to my truck since replacing the head gasket several years ago. Maybe I should refill it this fall.
 
Well, if it smells objectionable and I won't drink it, then I won't put it in my car. San Francisco has terrible tap water. Frequently I can see even sediment.
lol.gif
 
Thanks for the feedback guys. Especially those who DO remember 9th grade chemistry (unlike me).

Ken2, you appear to have a hole too. Cavitation is more a mechanical, than chemical phenomenon. Unless those additives you mention significantly increased the viscosity of the fluid, they will NOT prevent cavitation. I may not know my chemistry well, but I know my hydraulics. Cavitation can be a very destructive force in a pumped system.

I need to digest all your input for a while. Thanks all.
 
Good info! Well I am changing my intake manifold gasket and had to remove some hoses and lost some coolant...so now I figure I will just drain the rest and refill with Zerex G05 and DISTILLED WATER
cheers.gif
 
I spent a lot of time on this water subject a few years ago. Based on everything I could find to review I've elected to use rain water for all of my radiator and battery water needs. I believe it is the best water to use if it is available. I probably use better water in my cars than my family gets to drink. I do not use tap or distilled water.
 
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