Antifreeze recommendations?

[Yager200i]

Still haven't had a chance to ride my Yager! Recovering from foot surgery, and it's been raining and cold here.

In reading through the user manual for the Kymco Yager GT 200i, I notice this blurb:
"Using coolant with silicate inhibitors may cause premature wear of water pump seals or blockage of radiator passages."

1) What names do the silicate inhibitors go by in name-brand antifreezes, so I know which antifreeze to avoid?

2) Can we use the new low-silicate ethylene glycol antifreezes that are available?

3) What does everyone else use? What's the best antifreeze to use for this scooter?

4) Does anyone use Water-Wetter? Do you recommend doing so?

5) What color is the antifreeze that comes with the bike from the dealer? I know there's a little view-port on the overflow tank that you're supposed to check, but I can't see anything there. You'd think it'd be the standard green or orange or red color, but I see nothing. I'll take the access cover for the overflow tank off tomorrow, and see what I can see.

[MaryK]

Prestone 50:50 premixed antifreeze says no silicates on the label.
Oreilly's 50:50 looks to be made by Prestone and has the same ingredients.
They  are the ones we use.

Scoot Safely,

[Yager200i]

So I went to Kragen and did some perusing of their antifreeze offerings. If I didn't know better, I'd think the anti-freeze manufacturers were TRYING to make it as difficult as possible to choose the correct anti-freeze product for any particular application.

===============

COLOR NOTE:
The color of anti-freeze is no indication that it will work in your system! The color is only a dye, and gives no indication that it is the proper anti-freeze for your particular coolant system.

DEXCOOL NOTE:
DexCool is not a specific formula, it just denotes that the anti-freeze product passed GM's testing requirements. All three brands that have the label (Texaco Havoline, Prestone Extended Life and Zerex Extended Life) are somewhat similar. In particular, they’re OAT (Organic Acid Technology) coolants. All DexCool-approved coolants to date use two organic acid rust/corrosion inhibitors, one called sebacate, the other called 2-EHA (which stands for 2-ethylhexanoic acid).

INGREDIENT NOTES:
The ingredients listed below are found in various anti-freeze products. The notes on the ingredients are what I could glean from various internet resources.

===============

INGREDIENTS:

NJTSRN QT1:
The ingredient NJTSRN QT1 (New Jersey Trade Secret Registration Number QT1) is a trademark secret, owned by CCI Manufacturing (cci-il.com). Since it is a trademarked secret ingredient, no one except CCI knows the actual chemical makeup of this ingredient. Hence, it is unknown what effect this ingredient might have upon your system. As such, I can't recommend that anyone use any anti-freeze which lists NJTSRN QT1 as an ingredient. This was listed as an ingredient in Kragen's 'OReilly Extended Life Universal' and Peak 'Long Life 50/50'.

POTASSIUM 2-ETHYL HEXANOATE:
DO NOT USE THIS INGREDIENT! This is an OAT (Organic Acid Technology) ingredient. If the least bit of air gets into your system, it will turn into a rusty-colored sludge that will plug up coolant passages (i.e.: Dexcool used it, and has gained the nickname 'DeathCool'). Your coolant expansion tank will sludge up, since it is exposed to air. OAT anti-freeze ingredients take a long time to lay down a protective layer of metal oxide (the passivation layer) to protect the metal. Hence, if your water pump is cavitating and exposing fresh metal (as I suspect ours do, with the high RPMs developed), OAT will not work quickly enough to protect it. The result will be a badly corroded and eroded pump impellar. This was not listed on any of the anti-freeze products I looked at, but is known to be used in some Dex-Cool anti-freeze products.

SODIUM 2-ETHYL HEXANOATE:
This is an OAT (Organic Acid Technology) ingredient. This carries a similar warning to Potassium 2-Ethyl Hexanoate above. In addition, it is a plasticizer (softens plastic) that degrades certain gasket materials. OAT anti-freeze ingredients take a long time to lay down a protective layer of metal oxide (the passivation layer) to protect the metal. Hence, if your water pump is cavitating and exposing fresh metal (as I suspect ours do, with the high RPMs developed), OAT will not work quickly enough to protect it. The result will be a badly corroded and eroded pump impellar. This was listed as an ingredient in Prestone 'Extended Life 50/50'.

SODIUM NEODECANOATE:
This ingredient is an acidic buffer, what is known as OAT (Organic Acid Technology). Laboratory testing is impressive with this stuff, but real-world results are less impressive (i.e.: it's been found that once the OAT technology buffers are contaminated with rust, their buffering capacity falls off greatly, and corrosion rates increase). OAT anti-freeze ingredients take a long time to lay down a protective layer of metal oxide (the passivation layer) to protect the metal. Hence, if your water pump is cavitating and exposing fresh metal (as I suspect ours do, with the high RPMs developed), OAT will not work quickly enough to protect it. The result will be a badly corroded and eroded pump impellar. This was listed on the Prestone Extended Life 50/50, and is known to be used in some Dex-Cool anti-freeze products.

DENATONIUM BENZOATE:
This is what is known as a 'bittering agent'. It is used to make the anti-freeze taste bitter to pets and children, and has been suggested by lawmakers as an additive for said purposes. It is unknown what effects this chemical has on engine components. This ingredient was not listed on any of the anti-freeze products I looked at.

BENZOATE:
A component of OAT (Organic Acid Technology), an acidic buffer. Using solely OAT coolant is something to avoid with our scooters. OAT anti-freeze ingredients take a long time to lay down a protective layer of metal oxide (the passivation layer) to protect the metal. Hence, if your water pump is cavitating and exposing fresh metal (as I suspect ours do, with the high RPMs developed), OAT will not work quickly enough to protect it. The result will be a badly corroded and eroded pump impellar. None of the anti-freeze products I looked at listed this as an ingredient.

SEBACATE:
A component of OAT (Organic Acid Technology), an acidic buffer. Not as effective at corrosion protection at lower pH levels. Again, using solely OAT coolant is something to avoid with our scooters. OAT anti-freeze ingredients take a long time to lay down a protective layer of metal oxide (the passivation layer) to protect the metal. Hence, if your water pump is cavitating and exposing fresh metal (as I suspect ours do, with the high RPMs developed), OAT will not work quickly enough to protect it. The result will be a badly corroded and eroded pump impellar. None of the anti-freeze products I looked at listed this as an ingredient.

BORATE:
A component of OAT (Organic Acid Technology), an acidic buffer. Can attack aluminum if silicate levels are low (and modern anti-freeze products mostly contain low silicate levels). Again, using solely OAT coolant is something to avoid with our scooters. OAT anti-freeze ingredients take a long time to lay down a protective layer of metal oxide (the passivation layer) to protect the metal. Hence, if your water pump is cavitating and exposing fresh metal (as I suspect ours do, with the high RPMs developed), OAT will not work quickly enough to protect it. The result will be a badly corroded and eroded pump impellar. None of the anti-freeze products I looked at listed this as an ingredient.

PHOSPHATE:
Particularly effective in protecting water pumps from corrosion after cavitation erosion. Phosphate is known to precipitate in hard water, so you MUST use distilled water for any phosphate-based anti-freeze products, or you'll get sludge. None of the anti-freeze products I looked at listed this as an ingredient.

===============

METALS:
----------
Aluminum corrosion is best inhibited by silicate and most poorly by phosphate and borate.

Cast aluminum corrosion is best inhibited by silicate and most poorly by phosphate and molybdate.

Copper corrosion is best inhibited by molybdate and most poorly by benzoate.

High-lead solder corrosion is best inhibited by molybdate and phosphate and most poorly by nitrate, silicate and benzoate.

Low-lead solder corrosion is best inhibited by tolytriazole and molybdate and most poorly by nitrate and silicate.

Mild steel corrosion is best inhibited by molybdate, phosphate and nitrite and most poorly by tolytriazole and benzoate.

Gray cast iron corrosion is best inhibited by nitrate and most poorly by benzoate, tolytriazole, and borate.
----------

CHEMICALS:
----------
Phosphate is the most ubiquitous and most controversial inhibitor. It is a well known inhibitor of ferrous metal corrosion. Europeans specify non-phosphate coolants because phosphates have a propensity to precipitate in hard water (and most European water is hard water). Also, phosphates can cause a negative corrosion rate of aluminum (i.e.: not only does the aluminum not corrode, but free aluminum molecules in the coolant will re-attach to the aluminum engine components). This beneficial effect peaks at concentrations of about 3 gm/liter and decreases at both lower and higher concentrations. Typical concentrations in coolants range from 0 to 8 g/l.

Nitrate is included in virtually all coolant formulations because of its efficacy in preventing aluminum radiator pitting, with presumably no negative side effects for other metals. A typical concentration is 2 g/l.

Tolytriazole is similarly included in virtually all formulations owing to its effectiveness in preventing cupreous (copper-based) metal corrosion. A typical concentration is 1 g/l.

Molybdate is a broadly beneficial additive. It prevents corrosion in many metals and acts synergistically with phosphates and silicates to prevent corrosion in others. Molybdate also seems to prevent cavitation damage; it is usually selected to perform this function in non-phosphate coolants. Typical molybdate concentrations are 2 to 3 g/l.

Borate is the most commonly used buffer for coolant systems. Off the shelf, American coolants tend to have a pH of 10 or higher (this is an alkaline pH), while European coolants tend to have a pH of 7 to 8.5 (which is near neutral to very slightly alkaline). In service, the pH of American coolants often drops to 8. Unfortunately, borate tends to have a direct and negative effect on aluminum corrosion. In spite of this, the importance of keeping coolants well buffered is great enough to keep borate in coolant formulations. A typical concentration is 4 g/l.

Benzoate (and Nitrite, which is not mentioned here) are part of the British Standards Institute's [BSI] Corrosion Inhibited Ethanediol Anti-freeze formulation. Benzoate is more common in European coolants than American coolants and is described as a ferrous metals corrosion inhibitor.

Silicates are necessary in the protection of aluminum. The problem is that silicates are not indefinitely stable in solution. Other additives can be used to stabilize silicates somewhat. The lifespan of coolants could be considered by the presence of an adequate silicate concentration. 2 g/l is an effective concentration of silicate.
----------

===============

Here are the anti-freeze products I looked at:
Oreilly Extended Life Universal -
Ingredients: Ethylene Glycol, Di-Ethylene Glycol, Water, NJTSRN QT1

Peak Long Life 50/50 -
Ingredients: Ethylene Glycol, Di-Ethylene Glycol, Water, NJTSRN QT1

Prestone Extended Life 50/50 -
Ingredients: Ethylene Glycol, Di-Ethylene Glycol, Sodium 2-Ethyl Hexanoate, Sodium Neodecanoate

OReilly Antifreeze and Coolant (Black Bottle) -
Ingredients: Ethylene Glycol, Di-Ethylene Glycol, Water

NOTE: Most ethylene glycol antifreeze contains a few percent diethylene glycol, present as an inadvertent byproduct of ethylene glycol production.
===============

I chose the OReilly Antifreeze and Coolant (Black Bottle), simply because it doesn't list any ingredients known to be harmful to our type of engine.

===============

I also bought some Water-Wetter. The basic marketing premise behind Water-Wetter is that it reduces the surface tension of water. It also contains anti-corrosion ingredients.

Should localized boiling occur in the cylinder head coolant passages, the steam bubbles would form, come into contact with cooler surrounding coolant and collapse, which creates shock waves that can strip the protective metal oxide layer from the coolant passage.

Should your water pump cavitate (i.e.: turn so fast that it literally lowers the suction pressure so much that the liquid flashes to steam), the same effect would take place, with the collapsing steam bubbles stripping off the pump impellar's protective passivation layer.

Water-Wetter claims to attack this problem in two ways:
1) It reduces the surface tension of these bubbles, allowing for smaller bubble formation and hence smaller shockwaves, and hence less metal oxide (passivation) layer erosion.

2) The anti-corrosion ingredients help to quickly form a new protective metal oxide layer in those instances where the old layer has been stripped off.

Here are the ingredients of Water-Wetter, according to its MSDS (Material Safety Data Sheet):
http://www.redlineoil.com/content/files/tech/WaterWetter%20MSDS.pdf

---------------
1) Di-isopropyl alcohol ether: 1-40%
(Note: They mis-spell this in the MSDS as 'Dilsopropyl alcohol ether'.)
(Note: The listed CAS #25265-71-8 is for dipropylene glycol.)

2) Tri-isopropyl alcohol diether: 1-40%
(Note: The listed CAS #24800-44-0 is for tripropylene glycol.)

3) Sodium molybdate: 2-10%
(Note: The listed CAS #10102-40-6 is for molybdic acid sodium salt dihydrate.)

4) Tolyltriazole: 1-3%
(Note: The listed CAS #29385-43-1 is for tolyltriazole.)

5) Polysiloxane polymer: n/a
---------------

NOTE: There is no such thing as Di-isopropyl alcohol ether (or Dilsopropyl alcohol ether). The CAS number on the Water-Wetter MSDS is actually dipropylene glycol.

NOTE: There is no such thing as Tri-isopropyl alcohol diether. The CAS number on the Water-Wetter MSDS is actually tripropylene glycol.

The anti-corrosion ingredients are Sodium Molybdate and Tolyltriazole.

The Polysiloxane polymer acts as a stabilizer for the silicates in the propylene glycol, preventing it from coming out of solution.

So, it would appear that Water-Wetter is nothing more than propylene glycol anti-freeze (silicate-based), with sodium molybdate and tolyltriazole anti-corrosion ingredients, with a silicate stabilizer.

Note that you can mix ethylene glycol and propylene glycol together, but doing so makes it impossible to check the coolant's strength using a hydrometer, owing to the differences in the specific gravities of the two coolants.


RedLine makes the following claims:
-----
CLAIM: Unique agent for cooling systems that doubles the wetting ability of water

Yes, of course it increases the 'wetting ability', if compared to straight water with no additives. So does regular old ethylene glycol and propylene glycol anti-freeze.
-----
CLAIM: Rust and corrosion protection allows for use of straight water in racing or reduced antifreeze levels in warm climates

Water-wetter does provide corrosion-protection chemicals that may not be in your existing anti-freeze. If those chemicals are already in your existing anti-freeze, then Water-Wetter provides no additional benefit in this regard.

As for the 'reduced antifreeze levels' (which should read 'reduced antifreeze concentration' to avoid confusion) claim, that's because Water-Wetter IS primarily anti-freeze. You're simply swapping ethylene glycol for propylene glycol.
-----
CLAIM: Improves heat transfer and reduces cylinder head temperature

Again, over straight water, this would be true. While straight water has greater heat transfer capabilities than either ethylene glycol or propylene glycol, that is only up to the boiling point of water. Once you exceed that point, the heat transfer capability of straight water declines precipitously, because the boiling leads to less metal being exposed to water and more being exposed to steam (note that if you had enough coolant flow to strip the bubbles from the metal surface, you would actually see an increased heat transfer capability when boiling occurred, but then you'd also have high enough flow to erode the aluminum oxide passivation layer, which would result in rapid corrosion).

So by adding Water-Wetter to straight water, you're increasing the 'wetting ability' of the water, allowing smaller steam bubbles to form during boiling, and as such, increasing the capability of the fluid to transfer heat. That said, regular old propylene glycol will do the same thing (as would regular old ethylene glycol).

In addition, in older engines which have only run water as their coolant, there may be scale lining the radiator tubes and cylinder coolant passages. The addition of Water-Wetter may help to loosen and remove that scale, thereby increasing the heat transfer capabilities. For new engines, Water-Wetter would provide no benefit in this regard.

Extensive dyno testing has proven that the heat transfer capabilities fall within the margins of testing error when comparing straight water to water + Water Wetter, and when comparing a 50:50 antifreeze:water mixture to that same mixture supplemented with Water Wetter.
-----
CLAIM: May allow more spark advance for increase power and efficiency

This would be true for straight water based coolant systems that are 'on the edge' in regards to being able to dump engine heat. For systems that are capable of dumping engine heat easily, or for ethylene glycol or propylene glycol based coolant systems, Water-Wetter would provide no benefit in this regard.
-----
CLAIM: Compatible with new or used antifreeze (including DEX-COOL and long-life versions) to improve the heat transfer of ethylene and propylene glycol systems

For ethylene glycol based coolant systems, I can see where this would be true. For propylene glycol based coolant systems, I can't see how adding more propylene glycol (which is the primary component of Water-Wetter) would make a difference.
-----
CLAIM: Satisfies ASTM D2570 and ASTM D1384 corrosion tests for glycol-based antifreezes

This much is true.
-----

Another aside... it has been said that some motorcycle tracks don't allow ethylene glycol or propylene glycol coolant when racing, because a crash leading to a coolant leak would leave a slick spot that could be dangerous to racers. Yet, they allow straight water and Water-Wetter. Considering that Water-Wetter is primarily propylene glycol, perhaps those race tracks should rethink this policy.
===============

[Hoolander2]

I agree, it's as if they are trying to make it difficult to choose.  I eventually chose based on which one specifically said "no silicates" which was Prestone 50-50. 

That polysiloxane makes my paranoid mind suspicious since it has "silo" in the name.

Don't know about the color of the factory stuff. 

I bought my Xciting used and the water pump started leaking soon after.  I can only guess the original owner put something in which wasn't right.  I replaced the pump and flushed the system with lots of distilled water first.  The anti-freeze that I drained out was a weird color like it was a mix of different brands.  It also had what looked to me like tiny bits or flakes of metal, presumably aluminum, in it. The old water pump itself had corrosion started on the metal hose connection extensions.  I have had no problems since I put the Prestone in.   

[Yager200i]

It seems that we're backed into a corner, somewhat.

We can use silicates to protect the aluminum engine components from corrosion very effectively, but if we do so, we risk ruining our water pump mechanical seals. Or, we can run the new organic acid technology coolants, and risk getting into a 'DeathCool' situation (whereby the coolant turns to a rust-colored sludge that plugs coolant passages, when air is let into the radiator by opening the cap), and will still almost inevitably ruin our water pump impellar (since organic acid technology (OAT) coolants take a long time to lay down the protective passivation layer after it's been stripped off due to cavitation, too long of a time to provide protection to the pump impellar), or get pitting corrosion on our cylinder coolant passages (again, because OAT coolants take a long time to lay down a protective passivation layer, and that layer gets stripped off again quickly if localized boiling occurs at the cylinder head coolant passages).

Thanks, Kymco. What, the extra few dollars of a magnetic-drive water pump WITHOUT seals was too much? Sheesh.


So, what are the best pH conditions, chemical conditions and best chemicals (besides silicates) for aluminum corrosion prevention?

pH CONSIDERATIONS:
====================
It would appear that a more neutral / slightly alkaline pH (~8 - 9) is best for aluminum. This allows the protective passivation layer to form, and the passivation layer and base metal aren't attacked as much as in high-pH or low-pH environments. This pH is also high enough that if you're running silicate-based coolant or additives (including Water-Wetter), it will keep the silicate in solution and prevent it from forming globules that can clog coolant passages.

Next best would be a high-pH condition, in which the passivation layer is attacked more (leading to general corrosion, rather than pitting corrosion). In a high-pH environment, since it tends to attack the passivation layer, which is tougher than the base metal, corrosion damage is lower than in a low-pH environment. Although a high-pH environment prohibits passivation (i.e.: the formation of a protective layer) somewhat, the high-pH environment won't attack the base metal as much as a low-pH environment.

The worst would appear to be a low-pH environment, in which the base metal is attacked more (leading to pitting in areas where the passivation layer is removed, although the passivation layer can very quickly re-establish itself). In areas where the passivation layer is quickly scrubbed off (i.e.: the water pump during cavitation, cylinder coolant passages during boiling), a low-pH environment would be deadly to the metal. In addition to the metal being attacked, if you're running silicate-based coolant (or have any additives which contain even the smallest amounts of silicates, such as Water-Wetter), you'll find the silicates coming out of solution in a low-pH environment to form globules which can plug coolant passages.

European anti-freeze products generally have a neutral to slightly alkaline pH range (7 - 8.5), whereas American anti-freeze products generally have a more alkaline pH range (10 - 11) that drops over time as the alkalinity buffers are used up. If European anti-freeze products also experience a similar drop in pH over time (and why wouldn't they? Their alkalinity buffers are also used up for the same reason our coolant's alkalinity buffers are used up), that would put them in the worst pH condition over time.
====================


WATER CONSIDERATIONS:
====================
Since pH is so important, another consideration is the pH of the water you are using to dilute the antifreeze! If you're using low-pH water (i.e.: tap water which has a lower-than-neutral pH, or distilled water that has sat open for a long time), this will offset the higher-pH of the antifreeze, and cause a lower overall pH, which may cause problems down the road as the pH buffers in the coolant are used up. So don't use tap water! Use distilled, neutral-pH water (newly distilled water without anything added to it should be pH-neutral, since any pH-altering substances can't make it through the distillation process to end up in the condensate).

Now, you'll notice that I said "distilled water without anything added to it SHOULD be pH-neutral". This is because after the distillation process, distilled water will tend to absorb carbon dioxide (CO2), making it more acidic (lower pH). So, if you've got a new bottle of distilled water from the store, don't let it sit around open. Keep the lid on tight. Distilled water pH can go as low as 5.6 if it has absorbed enough carbon dioxide.
====================


CHEMICAL CONSIDERATIONS:
====================
Well, this is a more complicated subject than I can discuss here, so I'll provide a link:
http://books.google.com/books?id=kSHykGbjapMC&pg=PA1&lpg=PA1&dq=Engine+Coolant+Testing,+2nd+Symposium&source=bl&ots=FvGvZbqFbT&sig=99fJ2TXKZccBNbv6wm7z3OaSnrk&hl=en&ei=jiljTc_KKY_2tgOrzoGuCw&sa=X&oi=book_result&ct=result&resnum=9&ved=0CEMQ6AEwCA#v=onepage&q&f=false

This is a book called 'Engine Coolant Testing, 3rd Volume'. Look on pages 15-17, and you'll see various chemicals used for corrosion control during testing.

Monoacid-dibasic acid technology:
Sample A - Triazole, Monoacid, Dibasic Acid

Nitrite-free formulation:
Sample B - Borax, Sodium Benzoate, Sodium Nitrate (NaNO3), Triazole, Sodium Silicate (NaSiO3), Monoacid

Conventional benzoate-nitrite-silicate technology, high silicate:
Sample C - Borax, Sodium Benzoate, Sodium Nitrite (NaNO2), Sodium Nitrate (NaNO3), Sodium Silicate (NaSiO3)

Conventional benzoate-nitrite-silicate technology, low silicate:
Sample D - Borax, Sodium Benzoate, Sodium Nitrite (NaNO2), Sodium Nitrate (NaNO3), Triazole, Sodium Silicate (NaSiO3)

Inorganic phosphate technology:
Sample E - Borax, Sodium Nitrate (NaNO3), Triazole, Sodium Silicate (NaSiO3), Phosphoric Acid

Triethanol Amine Phosphate technology:
Sample F - Borax, Triazole, Phosphoric Acid, Triethanol Amine

The two test metals were:
(1) Aluminum SAE 329 (cast aluminum)
(2) Aluminum Alloy 6082 (wrought aluminum)

And looking at the corrosion rate test results:
Sample A - (1) 0.30 (2) 0.09
Sample B - (1) 0.39 (2) 6.73
Sample C - (1) 0.21 (2) -0.05
Sample D - (1) 0.07 (2) -0.06
Sample E - (1) 0.00 (2) -0.05
Sample F - (1) 0.29 (2) 0.76

(Negative values indicate a weight gain.)

This was under static heat-transfer conditions.

Things look a bit different under dynamic heat-transfer conditions (we'll only look at the SAE 329 test, since we're dealing with cast aluminum engine blocks):
SAMPLE - TEST DURATION(hrs) : CORROSION RESULT
A - 48:10.7  69:26.0  116:21.6
B - 48:512  69:N/A  116:N/A
C - 48:-18.0  69:261  116:N/A
D - 48:N/A  69:1260  116:N/A
E - 48:607  69:1243  116:N/A
F - 48:N/A  69:1510  116:N/A

(Negative values indicate a weight gain.)

The book states:
"Low silicate conventional coolants and the phosphate coolants showed high corrosion rates, even after a test duration of only 48 hours."

The book goes on to state:
"The high silicate conventional coolant (Sample C) performed well, but high corrosion rates were found when the test duration was extended to 69 hours. The monoacid-diacid coolant (Sample A) showed consistently low corrosion, even when the test duration was extended to 116 hours and aged test solutions were used."

So, it would appear that the new organic acid technology coolants are the best for usage. The problem is, the anti-freeze product manufacturers still haven't perfected the technology, leading to 'DeathCool' situations that ruin engines.

As such, I'm going to run conventional low-silicate coolant with Water-Wetter (which will add some silicates), and flush/change annually. This WILL be harder on my water pump mechanical seal than running the new organic acid technology anti-freeze products, but at least I know I won't undergo 'DeathCool' (i.e.: the coolant turning to a rust-colored sludge that blocks the coolant passages, simply because I popped open the radiator cap to check the radiator condition and by so doing let in a bit of air). And replacing the pump mechanical seal isn't all that hard. I replace mechanical seals on (very large) pumps at work. The advantage to being a 'wrench'.

If I find that the mechanical seal tends to go out pretty quickly with this regimen, I'll convert the water pump to magnetic drive (hence, it'll have no seal to wear out). This is something Kymco should consider doing for all its scooters. Then we could run the best anti-freeze formulation (high silicate) for our aluminum blocks, with no worries that the water pump mechanical seals will fail.
====================


OTHER CONSIDERATIONS:
====================
As an aside, did you know that if you're doing any engine work on an aluminum block engine, you SHOULD NOT use a graphite pencil to make any marks on the aluminum? Apparently, the dissimilar metals (aluminum, graphite) set up a localized galvanic corrosion that can strip away aluminum's oxide layer and allow greater overall pitting corrosion in that area.

Another aside, if you're considering cleaning your scooter with carbon tetrachloride and methyl alcohol, don't do it. Apparently some aluminum alloys react violently with the combination of carbon tetrachloride and methyl alcohol, which is strange considering that aluminum is resistant to each of those chemicals alone.
====================

[Yager200i]

Ok, after going through literally dozens upon dozens of different antifreeze concoctions, I believe I've found one that'll work well in our scooters.

Valvoline Zerex Asian Vehicle Antifreeze/Coolant
http://www.valvoline.com/products/brands/zerex/antifreeze/105

This is an ethylene glycol phosphated hybrid organic acid technology coolant, silicate free, plasticizer free,  it contains no borates, no 2-ethylhexanoic acid (2-EHA), no amines and no nitrites. It is especially good at protecting aluminum, and specifically good at protecting aluminum water pumps from cavitation corrosion.

It is available by request at Napa and O'Reilly auto parts stores.

A side benefit (for me, at least, since the wife drives a Hyundai), is that it'll work great in the car, as well.

[Vivo]

To simplify things, just use ethelyne glycol with silicates and flush (back flush)  and change your coolant regularly... 

[Yager200i]

To simplify things, just use ethelyne glycol with silicates and flush (back flush)  and change your coolant regularly...  ;)

I'm hoping the winkie face emoticon above means you were only kidding.

Since silicates aren't 100% soluble in water,  they tend to settle out under certain conditions. They specifically accumulate in certain areas of the coolant system, one of them being the pump seals, which they then chew up. So using an old-fashioned high-silicate coolant will probably chew up your pump seals pretty badly. There are low-silicate coolants, but they only mitigate the problem by including other chemicals that sometimes make for worse problems (plasticizers, chemicals that plate out in the cooler areas like the radiator, etc.).

I looked far and wide for a coolant that'd be exactly right for our scooter, and the Zerex Asian Vehicle is as close as we can get to perfect.

[Vivo]

I'm hoping the winkie face emoticon above means you were only kidding.

Since silicates aren't 100% soluble in water,  they tend to settle out under certain conditions. They specifically accumulate in certain areas of the coolant system, one of them being the pump seals, which they then chew up. So using an old-fashioned high-silicate coolant will probably chew up your pump seals pretty badly. There are low-silicate coolants, but they only mitigate the problem by including other chemicals that sometimes make for worse problems (plasticizers, chemicals that plate out in the cooler areas like the radiator, etc.).

I looked far and wide for a coolant that'd be exactly right for our scooter, and the Zerex Asian Vehicle is as close as we can get to perfect.

I wasn't kidding... the key words in my statement is "change coolant regularly" and "flushing"... Silicates are very good but they don't last a long time... they solidify and can cause problems in your cooling system... if time comes that it really chews up my pump seals,,, then by all means I'll just replace those seals....     There's no perfect oil, coolant, or fuel out there.... there are always arguments from your experienced drivers, manufacturers, chemical engineers, mechanical engineers, and marketing managers, ... and no one will win any argument....  As for me, I trust my experience with the product and up to what extent that I will stop "searching for the ultimate" oil, fuel, coolant, lubricants, tires, wax for my rides... I have a 1973 car, 1981 car, 1994, and 2006 car, and a 2011 Kymco... I've done my researches since the good ol' days.. up to this day.... and has come to a conclusion that... I have to spend most of my life enjoying riding and driving rather than wondering if a 93 octane is better than a 91 octance.... my two cents...   

However Sir, my compliments to your posts and research for a good product... this will surely help a lot of our friends here... Thank you for sharing...

[Yager200i]

I contacted Valvoline Zerex Product Support, just to be sure that I hadn't gone astray in my research... and if what they say is true, it's very surprising to me... here's what they wrote:

Thank you for contacting Zerex with your question.  We have verified that the scooter applications that you have provided information for, actually come factory filled with Dexcool Antifreeze/Coolant.  As a result of this, Zerex would recommend our Zerex Dexcool or the Zerex Asian Antifreeze/Coolant for use.

"come factory filled with Dexcool" !!!!!!?????

Wow, if that's the case, then perhaps it's not all Dexcool (aka Deathcool) that experiences the sludging problems that caused such a huge lawsuit not too long ago.

[MassScoot]

Geez...This thread makes me feel dizzy! Just change your coolant & move on already. Talk about a bloated thread.

[Vivo]

Geez...This thread makes me feel dizzy! Just change your coolant & move on already. Talk about a bloated thread.

I love rum on ice... 80 proof... no more, no less....    

[MotoRandy123]

 Well antifreeze has gotten surprisingly complicated in the last few years but there's no help
from the manufacturers on choosing a correct one. The vehicle manufacturers want you to buy
their antifreeze and the aftermarket wants you to use their's even though it might not be the
correct one for your vehicle.

 This is the first place I've found a relativity clear explanation of the chemicals involved. Now
where does the average citizen buy deionized water?

[Vivo]

As we call it in this part of the world... coolant... because we don't have winter here and no one will buy a product called "antifreeze".... anyway, the issue is not only antifreeze... you have motor oils, gasoline, and even other car care products that claim this and that... A Chemical Engineer will tell you one thing, a Mechanical Engineer will tell you another, and a Veteran Race Car driver will tell you even another thing.... result? confusion.... Well, for me, my principle is I need not protect my vehicle to last longer than myself in this world.. I just want to enjoy every bit of time driving and riding... ride safe!! 

Deionized water?  Some are sold in Car Accessories/Car Care stores... You can also use distilled drinking water...

[Yager200i]

Now where does the average citizen buy deionized water?

As long as you don't use just deionized water. Deionized water is just that... de-ionized. The first thing it will do is try to re-acquire those ions. That's a bad thing in an engine. But mixing it with coolant first allows the water to acquire the ions, so no metal damage is done to the engine.

Distilled water is just as pure, just as good, and cheaper... with a caveat. If you let the water sit around for a couple weeks in a container that isn't tightly sealed, it'll absorb CO₂ from the air, producing carbonic acid. This lowers the pH of the water to the point that it has the potential to screw up your coolant chemistry right from the get-go, leading to all sorts of problems, as discussed in posts above.

Reverse osmosis water is close to distilled in terms of quality, but the water quality varies with the quality of the R.O. equipment used, and the quality of the water that was input into the system in the first place.

Your best bet is to use water that's been distilled from good quality tap water, that's then run through a high quality R.O. system, but finding that water isn't easy. So just use distilled.