Distilled versus tap water
- Thread starter mjoekingz28
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If you can drink your tap water,then so can your car. Never had any coolant clogs. Salt air isn't good for AL,So my 2nd to last '88 528e came to me with a porous core. I didn't like the looks of the muddy coolant, so I back flushed the system . With tap water loaded with iron. I didn't expect coolant failure, so I made a 50/50 mix. When I brought the car to operating temps, I saw drips underneath. I drove the car 65 miles bringing it home with no troubles. ??? I lifted the hood and checked out the radiator. There were too many pin hole gushers to count. I'm laughing at the scene as I'm typing this. The brown glop must have been Bars Leak.
I have a TDS (Total Dissolved Solids) meter. It's a $6 item on eBay. I use it for maintaining my R/O system. It's basically a conductivity meter and doesn't give you the whole picture of your water quality. I basically shoot for a 90% or better "rejection ratio" from the R/O system (Input TDS - Output TDS)/Input TDS.
The interesting thing, which is not really surprising given how we get our tap water, is that the TDS of my tap water has more than doubled over the past 15 years. It was 110 when I first started measuring it around 1999-2000. It is now 250+. Not as bad as Corpus Christi's 600+, but still hard water. I would actually be more concerned about the smelly chlorine than the minerals.
The interesting thing, which is not really surprising given how we get our tap water, is that the TDS of my tap water has more than doubled over the past 15 years. It was 110 when I first started measuring it around 1999-2000. It is now 250+. Not as bad as Corpus Christi's 600+, but still hard water. I would actually be more concerned about the smelly chlorine than the minerals.
I used tap water (with Preston AM/AM or Peak Long Life) from garden hose in my 370+k miles Lexus for it entire life. The coolant system didn't have any problem, the radiator and water pump replaced once last year at around 360+k miles.
Tap water kills the radiator and water pump after 20 years and 360k miles is bad ? Distilled water can prolong the life of these two items longer (how much longer)?
Even I had good experience with tap water in my Lexus, I still use distilled water in my S2000. I love this car enough such that I rather spend few bucks to avoid possible problem(which I have no data to support this claim) with tap water in its coolant system.
Tap water kills the radiator and water pump after 20 years and 360k miles is bad ? Distilled water can prolong the life of these two items longer (how much longer)?
Even I had good experience with tap water in my Lexus, I still use distilled water in my S2000. I love this car enough such that I rather spend few bucks to avoid possible problem(which I have no data to support this claim) with tap water in its coolant system.
Distilled water has no minerals where tap water can have some calcium etc. But since your only changing your coolant maybe 5 times in the life of a car, the buildup would be pretty small, probably almost non-existent. Think of it this way, your house plumbing runs this water thru the fixtures day in and day out for decades and it takes many years before you have a problem. This is not an issue with a cars cooling system.
Well, Prestone recommends mixing with distilled. Havoline uses de-ionized in their 50/50.
So, it seemes, if your water is decent it doesnt matter. If this is the case, do batteries still require distilled? Any other uses for distilled water?
So, it seemes, if your water is decent it doesnt matter. If this is the case, do batteries still require distilled? Any other uses for distilled water?
Originally Posted By: 4wheeldog
Originally Posted By: Kestas
Originally Posted By: zach1900
I've heard that distilled water is actually worse for your cooling system, missing unstable ions always causing hotspots, I forget the exact mechanism, I'll try to find the article.
You're thinking of deionized water. It tries to strip metal from its base surface. But this phenomenon goes away the minute you splash antifreeze or dirty water into it. Use distilled or deionized water in your cooling system with confidence. I do.
We have deionized water on tap at work. I use it in all our coolant systems that produce swarf.
Don't use rain water. It has too much carboxylic acid in it.
What he said.....
I went to a boiler class years ago. The guy giving the class explained why deionized water was bad in boilers. He called it "Hungry water". He then tried to make the case that the same was true in your car's cooling system.
I waited until lunch to quiz him on this, and after lunch he amended his statement that, if you were not using antifreeze, deionized or distilled water were poor choices. With the use of 50% antifreeze, "Hungry water" has its needs satiated.
I see why your boiler feed water guy said what he said then after he thought about it modified it a little bit.
Let me give you guy’s a little more detailed information necessary to see what the best answer is in your particular situation. (when I design an HVAC/R system or do boilers this is critical because the industrial systems are radically different than the automotive systems and I have to explain it a lot because there’s a lot of maintenance guys out there who have innocently destroyed an industrial system because they tried to use automotive information thinking it was a 1:1 swap- it isn’t)
First off the “question” of tap vs. Distilled vs. DI etc. is wrong coming out of the gate because at that level it is not answerable.
It’s not a question- it’s actually an equation that will determine what the acceptable is for a specific cooling system. Even then the term “acceptable” has to be further defined because there are too many variables in the alphabet soup for a universal answer. This is why on industrial systems we also have to spec out the water quality standard based on system metallurgy and the selected coolant chemistry and other stuff for optimum performance.
If you define “acceptable” as the ability of heat exchange then all waters are identical.
If you define “acceptable” as long term efficiency and reliability in a system then you have to do some extra thinking and get some additional information. You also then need to factor in external factors such as maintenance intervals, system load and so forth. (This is where there is a fork in the road with what I do versus what a car owner will do because nobody “drives” an industrial HCU and they always run at a constant set of operational parameters and the fluid is tested frequently for system specific data points)
Basically water falls into a few basic categories and each have properties unique to it, random elements and other stuff. DI, DS (distilled), filtered, tap (city water) and ground
Everybody pretty much knows the differences but in basic terms DS is demineralized, DI has lower conductivity, tap, filtered and ground contain whatever they contain based on however they were processed.
Then you add the system metallurgy (some chemicals attack certain metals), the individual chemistry of the selected coolant, and sometimes even factor in transient electrical current from ungrounded components and there is a potential for damage. How much would depend on which part of the formula is affected and to what degree and whether the maintenance routine will mitigate it. You also can do things like sacrificial anodes and add buffers if required.
Not ever even thinking about testing a car system, if it were me, unless the antifreeze or car specified a specific recipe (which if they do they have a reason for it) then with a normal coolant maintenance program I doubt anyone would ever notice a significant difference in performance or reliability unless your water source was extreme in some random area of the equation.
Originally Posted By: Kestas
Originally Posted By: zach1900
I've heard that distilled water is actually worse for your cooling system, missing unstable ions always causing hotspots, I forget the exact mechanism, I'll try to find the article.
You're thinking of deionized water. It tries to strip metal from its base surface. But this phenomenon goes away the minute you splash antifreeze or dirty water into it. Use distilled or deionized water in your cooling system with confidence. I do.
We have deionized water on tap at work. I use it in all our coolant systems that produce swarf.
Don't use rain water. It has too much carboxylic acid in it.
What he said.....
I went to a boiler class years ago. The guy giving the class explained why deionized water was bad in boilers. He called it "Hungry water". He then tried to make the case that the same was true in your car's cooling system.
I waited until lunch to quiz him on this, and after lunch he amended his statement that, if you were not using antifreeze, deionized or distilled water were poor choices. With the use of 50% antifreeze, "Hungry water" has its needs satiated.
I see why your boiler feed water guy said what he said then after he thought about it modified it a little bit.
Let me give you guy’s a little more detailed information necessary to see what the best answer is in your particular situation. (when I design an HVAC/R system or do boilers this is critical because the industrial systems are radically different than the automotive systems and I have to explain it a lot because there’s a lot of maintenance guys out there who have innocently destroyed an industrial system because they tried to use automotive information thinking it was a 1:1 swap- it isn’t)
First off the “question” of tap vs. Distilled vs. DI etc. is wrong coming out of the gate because at that level it is not answerable.
It’s not a question- it’s actually an equation that will determine what the acceptable is for a specific cooling system. Even then the term “acceptable” has to be further defined because there are too many variables in the alphabet soup for a universal answer. This is why on industrial systems we also have to spec out the water quality standard based on system metallurgy and the selected coolant chemistry and other stuff for optimum performance.
If you define “acceptable” as the ability of heat exchange then all waters are identical.
If you define “acceptable” as long term efficiency and reliability in a system then you have to do some extra thinking and get some additional information. You also then need to factor in external factors such as maintenance intervals, system load and so forth. (This is where there is a fork in the road with what I do versus what a car owner will do because nobody “drives” an industrial HCU and they always run at a constant set of operational parameters and the fluid is tested frequently for system specific data points)
Basically water falls into a few basic categories and each have properties unique to it, random elements and other stuff. DI, DS (distilled), filtered, tap (city water) and ground
Everybody pretty much knows the differences but in basic terms DS is demineralized, DI has lower conductivity, tap, filtered and ground contain whatever they contain based on however they were processed.
Then you add the system metallurgy (some chemicals attack certain metals), the individual chemistry of the selected coolant, and sometimes even factor in transient electrical current from ungrounded components and there is a potential for damage. How much would depend on which part of the formula is affected and to what degree and whether the maintenance routine will mitigate it. You also can do things like sacrificial anodes and add buffers if required.
Not ever even thinking about testing a car system, if it were me, unless the antifreeze or car specified a specific recipe (which if they do they have a reason for it) then with a normal coolant maintenance program I doubt anyone would ever notice a significant difference in performance or reliability unless your water source was extreme in some random area of the equation.
I have used air conditioner condensate in the past, collected after rain because I assumed it would be less likely to have atmospheric dust in it then.
I suppose there might be some traces of say, lead from joint solder, etc, but I'd expect it would be pretty close to distilled.
I suppose there might be some traces of say, lead from joint solder, etc, but I'd expect it would be pretty close to distilled.
FWIW I always use tap water w/good results for the past 35 years.
The quality (in terms of mineral content) varies tremendously of course. When i lived in the City of Milwaukee we had Lake Michigan water which was very low in minerals. I never had to use anything but that water in my cooling system. Where I live now is well water (city wells) and the water is very hard. No way I would use that water, especially when a gallon of distilled is $0.90 at Walmart. It's not like you're using gallon upon gallon either.
Originally Posted By: philipp10
Distilled water has no minerals where tap water can have some calcium etc. But since your only changing your coolant maybe 5 times in the life of a car, the buildup would be pretty small, probably almost non-existent. Think of it this way, your house plumbing runs this water thru the fixtures day in and day out for decades and it takes many years before you have a problem. This is not an issue with a cars cooling system.
The only time you have calcium buildup is where you get evaporation and then constant replenishment (such as in a water heater, coffee maker, or anything that gets heated, drained, and refilled).
Shower heads get the same effect but much slower than active heated appliances.
Your cooling system water doesn't evaporate and it's not constantly refilled. If it does, you have more problems than the water you're using.
Distilled water has no minerals where tap water can have some calcium etc. But since your only changing your coolant maybe 5 times in the life of a car, the buildup would be pretty small, probably almost non-existent. Think of it this way, your house plumbing runs this water thru the fixtures day in and day out for decades and it takes many years before you have a problem. This is not an issue with a cars cooling system.
The only time you have calcium buildup is where you get evaporation and then constant replenishment (such as in a water heater, coffee maker, or anything that gets heated, drained, and refilled).
Shower heads get the same effect but much slower than active heated appliances.
Your cooling system water doesn't evaporate and it's not constantly refilled. If it does, you have more problems than the water you're using.
Last edited:
Originally Posted By: Subdued
Originally Posted By: philipp10
Distilled water has no minerals where tap water can have some calcium etc. But since your only changing your coolant maybe 5 times in the life of a car, the buildup would be pretty small, probably almost non-existent. Think of it this way, your house plumbing runs this water thru the fixtures day in and day out for decades and it takes many years before you have a problem. This is not an issue with a cars cooling system.
The only time you have calcium buildup is where you get evaporation and then constant replenishment (such as in a water heater, coffee maker, or anything that gets heated, drained, and refilled).
Shower heads get the same effect but much slower than active heated appliances.
Your cooling system water doesn't evaporate and it's not constantly refilled. If it does, you have more problems than the water you're using.
What causes the calcium carbonate build up is not necessarily evaporation. Calcium bicarbonate is very soluble in water. The heat drives off some of the carbonate in the form of carbon dioxide. Calcium carbonoate is what is left and it is not as soluble, so it precipitates out of solution and forms scale. This would also happen in your cooling system.
Originally Posted By: philipp10
Distilled water has no minerals where tap water can have some calcium etc. But since your only changing your coolant maybe 5 times in the life of a car, the buildup would be pretty small, probably almost non-existent. Think of it this way, your house plumbing runs this water thru the fixtures day in and day out for decades and it takes many years before you have a problem. This is not an issue with a cars cooling system.
The only time you have calcium buildup is where you get evaporation and then constant replenishment (such as in a water heater, coffee maker, or anything that gets heated, drained, and refilled).
Shower heads get the same effect but much slower than active heated appliances.
Your cooling system water doesn't evaporate and it's not constantly refilled. If it does, you have more problems than the water you're using.
What causes the calcium carbonate build up is not necessarily evaporation. Calcium bicarbonate is very soluble in water. The heat drives off some of the carbonate in the form of carbon dioxide. Calcium carbonoate is what is left and it is not as soluble, so it precipitates out of solution and forms scale. This would also happen in your cooling system.
In my unfiltered systems I use distilled. In my filtered systems, I use tap sometimes. It really is easier to mix using jugs of distilled though.
Originally Posted By: 4wheeldog
Originally Posted By: Kestas
Originally Posted By: zach1900
I've heard that distilled water is actually worse for your cooling system, missing unstable ions always causing hotspots, I forget the exact mechanism, I'll try to find the article.
You're thinking of deionized water. It tries to strip metal from its base surface. But this phenomenon goes away the minute you splash antifreeze or dirty water into it. Use distilled or deionized water in your cooling system with confidence. I do.
We have deionized water on tap at work. I use it in all our coolant systems that produce swarf.
Don't use rain water. It has too much carboxylic acid in it.
What he said.....
I went to a boiler class years ago. The guy giving the class explained why deionized water was bad in boilers. He called it "Hungry water". He then tried to make the case that the same was true in your car's cooling system.
I waited until lunch to quiz him on this, and after lunch he amended his statement that, if you were not using antifreeze, deionized or distilled water were poor choices. With the use of 50% antifreeze, "Hungry water" has its needs satiated.
A German car company used to say not to use deionized water.
Originally Posted By: Kestas
Originally Posted By: zach1900
I've heard that distilled water is actually worse for your cooling system, missing unstable ions always causing hotspots, I forget the exact mechanism, I'll try to find the article.
You're thinking of deionized water. It tries to strip metal from its base surface. But this phenomenon goes away the minute you splash antifreeze or dirty water into it. Use distilled or deionized water in your cooling system with confidence. I do.
We have deionized water on tap at work. I use it in all our coolant systems that produce swarf.
Don't use rain water. It has too much carboxylic acid in it.
What he said.....
I went to a boiler class years ago. The guy giving the class explained why deionized water was bad in boilers. He called it "Hungry water". He then tried to make the case that the same was true in your car's cooling system.
I waited until lunch to quiz him on this, and after lunch he amended his statement that, if you were not using antifreeze, deionized or distilled water were poor choices. With the use of 50% antifreeze, "Hungry water" has its needs satiated.
A German car company used to say not to use deionized water.
I worked in power generation for many years. We had both anion and cation trains to produce condensate good enough for our B&W steam generators. And on top of that, we installed polishers in the condensate system coming off of the hot wells.If you don't remove the minerals from the boiler water, you will wind up with power robbing deposition on the turbine blades and diaphragms..
At $1/gallon (I actually pay $.25 why even question it.
U R missing the point Al.
Which is 'better'?
Of course we'd pay the dollar if it was better, but the owner's manual says drinkable water, should we not use it. Ive heard we should not drink distilled. So if that is true, we would be spending more money for an inferior product, even when the half cent or so gallon of tap is the desired fluid.
Which is 'better'?
Of course we'd pay the dollar if it was better, but the owner's manual says drinkable water, should we not use it. Ive heard we should not drink distilled. So if that is true, we would be spending more money for an inferior product, even when the half cent or so gallon of tap is the desired fluid.
well if your like me, I maybe do one coolant change in the life of a car, around 125k miles (if at all) so this is not much of an issue. Of course I would use distilled but I cannot imagine that one coolant change with tap water would have THAT much calcium in it to be able to coat my cooling system to any worrisome degree.
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