Here are some points about coolants I've gathered from around the internet. Sorry its a boring subject but please feel free to correct any misunderstandings so we can all learn and get away from the vehicle industry using fear and uncertainty to sell its own products which are often unavailable locally.
I contacted Yamaha to ask what type of coolant Yamacool is, Si-HOAT or P-HOAT or just OAT etc? After a bit of a dance they wrote "Regarding the 2 type’s (silicates) Si-HOAT and (phosphates) P-HOAT: Both are be used in modern engines.
We would recommend which ever one is most accessible to you, as the service schedule will result in the coolant being changed before either coolant types have any issues." Notice it looks like "safe to" or "ok to" has been deleted from this sentence.
The Service Manual guideline is to use a "High-quality ethylene glycol based antifreeze containing corrosion inhibitors for aluminum engines", which is also not enough information to know for sure what to use if you want to use the best coolant type for a Yamaha engine, so you have to make some assumptions in order to determine the gold standard yourself. However, Yamaha are basically saying that as long as you replace the coolant according to the maintenance schedule then you will be fine... but I prefer to know that what I'm putting in is fine regardless of how soon I get it out of the system again!
Here are a few points:
1. Colour of coolant doesn't mean anything anymore, its just a dye added to the clear coolant liquid. For example Valvoline Zerex Asian Blue coolant is the same as Valvoline Zerex Asian Red coolant. If you have red coolant from the factory in your radiator, Valvoline don't want you to avoid their product because the colour is deferent so they provide the same coolant in 2 different colours.
2. IAT (Inorganic Acid Technology) coolant was used in old vehicles from decades ago. These days all vehicles have a version of OAT (Organic Acid Technology).
3. Never mix IAT and OAT coolant as it will likely react and form a gel in the system. However, IAT is unlikely to be in your system if you have a vehicle manufactured in the last 25 years!
4. It is best practice to flush out the cooling system with distilled water between coolant changes, especially if the coolant hasn't been changed in the last 5 years, and use a coolant flush additive if you are in any doubt (old vehicle/unsure about existing coolant type)
5. Silicates or phosphates are the most common corrosion protection additives used with OAT based coolant types. They are both synthetic additives giving rise to the Hybrid part of HOAT (Hybrid Organic Acid Technology) coolant type designation. A coolant using silicates or phosphates as a corrosion inhibitor can also be known as "Si-HOAT" and "P-HOAT" respectively.
6. Silicates can fall out of suspension from HOAT coolant and form a kind of white flake/powder in the coolant when it is cold. This quickly dissolves back into the coolant as it warms up so should be nothing to worry about.
7. Silicates form a protective layer in the coolant system to prevent the water in the coolant from corroding the cooling system, but silicates can be unkind to seals, gaskets and hoses over a long period, so are not ideal.
8. Instead of silicates, phosphates may be used to prevent corrosion in the coolant system. Phosphates are used mainly in Japanese/Asian cars because the tap water in Asia is not "Hard" water, which is water containing high levels of minerals (calcium and magnesium). The problem with phosphates and hard water is that the phosphates can react with the minerals to form a sludge which restricts flow in the cooling system. Presumably as many parts of Europe have hard tap water, P-HOAT coolant is not commonly available in Europe.
Elsewhere in the Yamaha Service Manual it suggests when mixing-up fresh antifreeze concentrate and water to make a coolant, to use only distilled water, or if that is not available to use "Soft" water ("Use only distilled water. However, if distilled water is not available, soft water may be used"). Soft water is water that has been treated, removing any calcium and magnesium. Yamaha could be implying that they use P-HOAT coolant from the factory and that Yamacool is in fact a P-HOAT coolant. However if P-HOAT was used, I would expect Yamaha to be more explicit that adding hard water could result in poor coolant flow and over-heating.
As for me, I live in Europe and intend to flush my bike's coolant system thoroughly and use Motorex M3.0 which is silicate and phosphate free and widely available so not too expensive. I think it should be classed as a HOAT coolant as its OAT with anti-corrosion additives making it a Hybrid OAT coolant, but Motorex only write "OAT" on their packaging. From then on I will stick to the same coolant type (silicate and phosphate free) for all subsequent coolant changes.
The only issue with M3.0 coolant is that it's light pink and is VERY hard to see through the side of a motorcycle's white plastic reservoir tank (even with a flashlight its almost impossible). I can see this putting a lot of motorcyclists off, come on Motorex, offer M3.0 in a darker colour!
Note: Motorex M5.0 is silicate based and used to be recommended (by KTM) for KTM motorbikes. However, several years ago KTM switched to M3.0, even for some bikes which used to be recommended to use M5.0... so don't go thinking M5.0 must be an advance on M3.0!
Another thing, if the coolant doesn't say silicate and/or phosphate free on the packaging or in their technical documentation, then assume it has one of those and avoid it.
This time I flushed with distilled water (as Yamaha didn't say what Yamacool coolant type actually is) and filled up with Motorex M3.0. But as I can't see what level the pink coolant level is at, next time I will flush again and refill with a blue (Polyston) coolant I found in my local hypermarket which specifically says "silicate and phosphate free".
Thanks to this great online resource and many other online contributors:
www.valvolineglobal.com
I contacted Yamaha to ask what type of coolant Yamacool is, Si-HOAT or P-HOAT or just OAT etc? After a bit of a dance they wrote "Regarding the 2 type’s (silicates) Si-HOAT and (phosphates) P-HOAT: Both are be used in modern engines.
We would recommend which ever one is most accessible to you, as the service schedule will result in the coolant being changed before either coolant types have any issues." Notice it looks like "safe to" or "ok to" has been deleted from this sentence.
The Service Manual guideline is to use a "High-quality ethylene glycol based antifreeze containing corrosion inhibitors for aluminum engines", which is also not enough information to know for sure what to use if you want to use the best coolant type for a Yamaha engine, so you have to make some assumptions in order to determine the gold standard yourself. However, Yamaha are basically saying that as long as you replace the coolant according to the maintenance schedule then you will be fine... but I prefer to know that what I'm putting in is fine regardless of how soon I get it out of the system again!
Here are a few points:
1. Colour of coolant doesn't mean anything anymore, its just a dye added to the clear coolant liquid. For example Valvoline Zerex Asian Blue coolant is the same as Valvoline Zerex Asian Red coolant. If you have red coolant from the factory in your radiator, Valvoline don't want you to avoid their product because the colour is deferent so they provide the same coolant in 2 different colours.
2. IAT (Inorganic Acid Technology) coolant was used in old vehicles from decades ago. These days all vehicles have a version of OAT (Organic Acid Technology).
3. Never mix IAT and OAT coolant as it will likely react and form a gel in the system. However, IAT is unlikely to be in your system if you have a vehicle manufactured in the last 25 years!
4. It is best practice to flush out the cooling system with distilled water between coolant changes, especially if the coolant hasn't been changed in the last 5 years, and use a coolant flush additive if you are in any doubt (old vehicle/unsure about existing coolant type)
5. Silicates or phosphates are the most common corrosion protection additives used with OAT based coolant types. They are both synthetic additives giving rise to the Hybrid part of HOAT (Hybrid Organic Acid Technology) coolant type designation. A coolant using silicates or phosphates as a corrosion inhibitor can also be known as "Si-HOAT" and "P-HOAT" respectively.
6. Silicates can fall out of suspension from HOAT coolant and form a kind of white flake/powder in the coolant when it is cold. This quickly dissolves back into the coolant as it warms up so should be nothing to worry about.
7. Silicates form a protective layer in the coolant system to prevent the water in the coolant from corroding the cooling system, but silicates can be unkind to seals, gaskets and hoses over a long period, so are not ideal.
8. Instead of silicates, phosphates may be used to prevent corrosion in the coolant system. Phosphates are used mainly in Japanese/Asian cars because the tap water in Asia is not "Hard" water, which is water containing high levels of minerals (calcium and magnesium). The problem with phosphates and hard water is that the phosphates can react with the minerals to form a sludge which restricts flow in the cooling system. Presumably as many parts of Europe have hard tap water, P-HOAT coolant is not commonly available in Europe.
Elsewhere in the Yamaha Service Manual it suggests when mixing-up fresh antifreeze concentrate and water to make a coolant, to use only distilled water, or if that is not available to use "Soft" water ("Use only distilled water. However, if distilled water is not available, soft water may be used"). Soft water is water that has been treated, removing any calcium and magnesium. Yamaha could be implying that they use P-HOAT coolant from the factory and that Yamacool is in fact a P-HOAT coolant. However if P-HOAT was used, I would expect Yamaha to be more explicit that adding hard water could result in poor coolant flow and over-heating.
As for me, I live in Europe and intend to flush my bike's coolant system thoroughly and use Motorex M3.0 which is silicate and phosphate free and widely available so not too expensive. I think it should be classed as a HOAT coolant as its OAT with anti-corrosion additives making it a Hybrid OAT coolant, but Motorex only write "OAT" on their packaging. From then on I will stick to the same coolant type (silicate and phosphate free) for all subsequent coolant changes.
The only issue with M3.0 coolant is that it's light pink and is VERY hard to see through the side of a motorcycle's white plastic reservoir tank (even with a flashlight its almost impossible). I can see this putting a lot of motorcyclists off, come on Motorex, offer M3.0 in a darker colour!
Note: Motorex M5.0 is silicate based and used to be recommended (by KTM) for KTM motorbikes. However, several years ago KTM switched to M3.0, even for some bikes which used to be recommended to use M5.0... so don't go thinking M5.0 must be an advance on M3.0!
Another thing, if the coolant doesn't say silicate and/or phosphate free on the packaging or in their technical documentation, then assume it has one of those and avoid it.
This time I flushed with distilled water (as Yamaha didn't say what Yamacool coolant type actually is) and filled up with Motorex M3.0. But as I can't see what level the pink coolant level is at, next time I will flush again and refill with a blue (Polyston) coolant I found in my local hypermarket which specifically says "silicate and phosphate free".
Thanks to this great online resource and many other online contributors:
THE COMPLETE GUIDE TO USING AND CHOOSING THE RIGHT CAR COOLANT - Valvoline™ Global Europe - EN
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