Distilled water to flush different colored coolant - OCD?

Joined
Jan 2, 2004
Messages
10,017
Location
California
One of the cars is due for a coolant change, current fill is Toyota pink SLLC. Two cars are on Prestone Cor-Guard, but whatever remaining pink coolant gave it a weird red-yellow color. I want to switch that car to Cor-Guard.

I know Prestone makes a red Toyota formula coolant but I like to keep as little coolant on hand as possible(I keep Asian pink Zerex around for hybrid inverters and the neighbor’s cars that are still under warranty). Am I being too OCD for wanting to do a distilled water flush to try to dilute the current coolant before installing the final fill?
 
Joined
Nov 3, 2013
Messages
2,106
Location
Northern Utah
Makes sense to me. Every good how-to on coolant system flush and fill always includes the flush. Note that the process is called Flush and fill.

I wouldn't let a little color change bother me, though. As long as you flush with water, and get out the majority of the old coolant, if just a little remains, and changes the color, it's OK.
 
Joined
Sep 26, 2021
Messages
83
Google it - it will say don’t use distilled water.

From the Rislone site

WHY YOU SHOULD NEVER USE DISTILLED WATER IN YOUR COOLING SYSTEM​

no-distilled-water.jpeg
We get this question all the time when talking to customers on our tech line: What is the best type of water to use in my cooling system?” In this post, we would like to address this topic, as the plethora of misinformation regarding this topic has easily made it the most misunderstood.
Many people have “heard” that distilled water is the best water to use in a cooling system. This is wrong! While it is certainly true that distilled water’s purity prevents electrolysis and scale/deposit formation, it unfortunately comes with a potentially very damaging side effect.

During the distillation process, water is vaporized into its gaseous phase, so all its impurities are left behind. These impurities include a number of minerals, including “calcium” and “magnesium,” the two components of water “hardness.” The water is then condensed back into its liquid phase, so the resulting liquid is pure water – in fact, some of the purest water on earth. But the problem is that when water is distilled, or “stripped,” of its minerals and impurities, the resulting solution is composed of chemically imbalanced “ions.” This leaves distilled water “ionically hungry,” so it will actually strip electrons from the metals in a cooling system as it attempts to chemically re-balance itself. As it chemically removes electrons from the metals of cooling system components, distilled water eventually does extreme damage that could lead to cooling system failure.

So what’s the answer? Softened water. During the water softening process, the same impurities and minerals are removed from water as during the distillation process – but with one very important distinction. Rather than STRIPPING the impurities from water, softening EXCHANGES the impurities with a sodium ion. The resulting solution is chemically and ionically balanced, making softened water very stable, very pure, and non-threatening to cooling system metals.

There seems to be a perceptual issue with regard to the usage of softened water in cooling systems by auto enthusiasts. Many mistakenly believe that because salt is added to water softeners, then softened water must contain salt, a substance of course known to be very corrosive. Nothing could be further from the truth. The salt you add to a water softener is NaCl, or sodium chloride.

During the softening process, only the sodium ion is exchanged into the water. Therefore, softened water does NOT contain corrosive salt.

What are the benefits of using softened water? Soft water lacks most of the impurities of tap water, meaning it far less conductive (i.e. less damage from electrolysis) and will not form deposits (i.e. less possibility of overheating). However, if you use Hy-per Lube Super Coolant, you don’t need to use softened water. Hy-per Lube Super Coolant contains molybdate, a form of the semi-precious metal “molybdenum,” which is proven to be extremely effective in preventing galvanic action and electrolysis – regardless of what type of water is used. Hy-Per Lube Super Coolant also contains polymer dispersants which keep water hardness in solution, thus preventing the formation of insulative scales and deposits. So regardless of whether you use softened water or tap water, you need not worry about these issues when you use Hy-Per Lube Super Coolant. This is actually one of the important benefits of the product, because not everybody has easy access to softened water.

But please – PLEASE! – do not use distilled water in your automotive cooling system.
 
Joined
Apr 8, 2019
Messages
822
Location
97045
Google it - it will say don’t use distilled water.

From the Rislone site

WHY YOU SHOULD NEVER USE DISTILLED WATER IN YOUR COOLING SYSTEM​

no-distilled-water.jpeg
We get this question all the time when talking to customers on our tech line: What is the best type of water to use in my cooling system?” In this post, we would like to address this topic, as the plethora of misinformation regarding this topic has easily made it the most misunderstood.
Many people have “heard” that distilled water is the best water to use in a cooling system. This is wrong! While it is certainly true that distilled water’s purity prevents electrolysis and scale/deposit formation, it unfortunately comes with a potentially very damaging side effect.

During the distillation process, water is vaporized into its gaseous phase, so all its impurities are left behind. These impurities include a number of minerals, including “calcium” and “magnesium,” the two components of water “hardness.” The water is then condensed back into its liquid phase, so the resulting liquid is pure water – in fact, some of the purest water on earth. But the problem is that when water is distilled, or “stripped,” of its minerals and impurities, the resulting solution is composed of chemically imbalanced “ions.” This leaves distilled water “ionically hungry,” so it will actually strip electrons from the metals in a cooling system as it attempts to chemically re-balance itself. As it chemically removes electrons from the metals of cooling system components, distilled water eventually does extreme damage that could lead to cooling system failure.

So what’s the answer? Softened water. During the water softening process, the same impurities and minerals are removed from water as during the distillation process – but with one very important distinction. Rather than STRIPPING the impurities from water, softening EXCHANGES the impurities with a sodium ion. The resulting solution is chemically and ionically balanced, making softened water very stable, very pure, and non-threatening to cooling system metals.

There seems to be a perceptual issue with regard to the usage of softened water in cooling systems by auto enthusiasts. Many mistakenly believe that because salt is added to water softeners, then softened water must contain salt, a substance of course known to be very corrosive. Nothing could be further from the truth. The salt you add to a water softener is NaCl, or sodium chloride.

During the softening process, only the sodium ion is exchanged into the water. Therefore, softened water does NOT contain corrosive salt.

What are the benefits of using softened water? Soft water lacks most of the impurities of tap water, meaning it far less conductive (i.e. less damage from electrolysis) and will not form deposits (i.e. less possibility of overheating). However, if you use Hy-per Lube Super Coolant, you don’t need to use softened water. Hy-per Lube Super Coolant contains molybdate, a form of the semi-precious metal “molybdenum,” which is proven to be extremely effective in preventing galvanic action and electrolysis – regardless of what type of water is used. Hy-Per Lube Super Coolant also contains polymer dispersants which keep water hardness in solution, thus preventing the formation of insulative scales and deposits. So regardless of whether you use softened water or tap water, you need not worry about these issues when you use Hy-Per Lube Super Coolant. This is actually one of the important benefits of the product, because not everybody has easy access to softened water.

But please – PLEASE! – do not use distilled water in your automotive cooling system.
Fuchs says just the opposite. I trust Fuchs way more than Rislone.

MAINTAIN FRICOFIN V has to be diluted before use. The recommended concentration is from minimum 35 % Volume up to 60%. It is also recommended to use demineralised or distilled water as well as drinkable tab water, if the values of the following Table are not exceeded.

  • Water hardness: 0 up to 20 °dGH (0-3,6 mmol/l)
  • Chlorine content: max. 100 ppm
  • Sulfate content: max. 100 ppm
 

pbm

Joined
Apr 19, 2004
Messages
9,484
Location
New York
I think so. My procedure is to drain, flush a few thermostat cycles with hose water until clear, drain, then fill with 50/50.
I flush with distilled water and use concentrate coolant (filling half the total capacity of the system with concentrate and then topping off with distilled water). There is always residual water left after flushing so by using 50/50 you may actually end up with 40/60 or even less. If I were to use 50/50 it would be just a drain and refill (no flush).
 
Joined
Jul 27, 2012
Messages
733
Location
Perth, Western Australia
I flush with distilled water and use concentrate coolant (filling half the total capacity of the system with concentrate and then topping off with distilled water).
I've done this for years. After one or more DI flushes there's essentially no coolant left, but there's always water. I dump in the correct volume of concentrate and then top up to the correct level. That way you're guaranteed to get the mix right first time, every time.

As for the DI water flush, I've done both. I've used 60L of DI water doing multiple flushes, and I've used copious quantities of hose water and a final 10L flush with DI water. 6 of one, half a dozen of the other. The latter is cheaper and if you were to calculate the final contamination in PPM it'd be in the "not worth worrying about". Admittedly our tap water is super soft, has low alkalinity and low chloramines.

The only issue I've ever had was the last time I changed coolant. I used the incoming coolant manufacturers flush and procedure, and within 12 months the cooling system was full of grunge and the coolant had lost all colour. They were "supposedly" compatible, but apparently not. A couple of days with a bottle of Cummins Restore, and a *lot* of flushes later and we're looking good after 12 months.
 
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Joined
Apr 15, 2010
Messages
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Location
Atlanta,GA
Google it - it will say don’t use distilled water.

From the Rislone site

WHY YOU SHOULD NEVER USE DISTILLED WATER IN YOUR COOLING SYSTEM​

no-distilled-water.jpeg
We get this question all the time when talking to customers on our tech line: What is the best type of water to use in my cooling system?” In this post, we would like to address this topic, as the plethora of misinformation regarding this topic has easily made it the most misunderstood.
Many people have “heard” that distilled water is the best water to use in a cooling system. This is wrong! While it is certainly true that distilled water’s purity prevents electrolysis and scale/deposit formation, it unfortunately comes with a potentially very damaging side effect.

During the distillation process, water is vaporized into its gaseous phase, so all its impurities are left behind. These impurities include a number of minerals, including “calcium” and “magnesium,” the two components of water “hardness.” The water is then condensed back into its liquid phase, so the resulting liquid is pure water – in fact, some of the purest water on earth. But the problem is that when water is distilled, or “stripped,” of its minerals and impurities, the resulting solution is composed of chemically imbalanced “ions.” This leaves distilled water “ionically hungry,” so it will actually strip electrons from the metals in a cooling system as it attempts to chemically re-balance itself. As it chemically removes electrons from the metals of cooling system components, distilled water eventually does extreme damage that could lead to cooling system failure.

So what’s the answer? Softened water. During the water softening process, the same impurities and minerals are removed from water as during the distillation process – but with one very important distinction. Rather than STRIPPING the impurities from water, softening EXCHANGES the impurities with a sodium ion. The resulting solution is chemically and ionically balanced, making softened water very stable, very pure, and non-threatening to cooling system metals.

There seems to be a perceptual issue with regard to the usage of softened water in cooling systems by auto enthusiasts. Many mistakenly believe that because salt is added to water softeners, then softened water must contain salt, a substance of course known to be very corrosive. Nothing could be further from the truth. The salt you add to a water softener is NaCl, or sodium chloride.

During the softening process, only the sodium ion is exchanged into the water. Therefore, softened water does NOT contain corrosive salt.

What are the benefits of using softened water? Soft water lacks most of the impurities of tap water, meaning it far less conductive (i.e. less damage from electrolysis) and will not form deposits (i.e. less possibility of overheating). However, if you use Hy-per Lube Super Coolant, you don’t need to use softened water. Hy-per Lube Super Coolant contains molybdate, a form of the semi-precious metal “molybdenum,” which is proven to be extremely effective in preventing galvanic action and electrolysis – regardless of what type of water is used. Hy-Per Lube Super Coolant also contains polymer dispersants which keep water hardness in solution, thus preventing the formation of insulative scales and deposits. So regardless of whether you use softened water or tap water, you need not worry about these issues when you use Hy-Per Lube Super Coolant. This is actually one of the important benefits of the product, because not everybody has easy access to softened water.

But please – PLEASE! – do not use distilled water in your automotive cooling system.
Basically Rislone is saying companies just want to sell you antifreeze and spec distilled water because it's convenient for the customer.
 
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