Motorcycle Special Coolant Question

[Harpo]

I've always heard liquid-cooled bikes require a silicate-free coolant ... and that automotive coolants are forbidden because they abrade the impeller seals. The maintenance manual for my ST1300 doesn't mention this ... so, does the ST use a different type of water pump that tolerates automotive antifreeze/water mix? That manual has a lot of mistakes in chapter six, so I don't really trust it. For instance, it only shows one block drain (right side) for coolant instead of two ... and it calls that a "cylinder drain" (page 6-6). I bought the expensive Honda motorcycle coolant to be on the safe side ... but could I have saved some money with an automotive coolant?

 

[T_C]

ST1300 definitely needs silicate free. The ceramic seal around the shaft on the water pump will get eaten very quickly due to the silicate.

I think if you check now days you will find most automotive coolant is silicate free. The tighter tolerances of the modern engines, new materials and longer life of the coolant itself has deemed the sand blasting of the old days to not be needed. The last two bottles of good old Prestone I bought were silicate free. But if it does not say it, do not assume it.

 

[SMSW]

I really don't know what you are supposed to use in the ST's cooling system, but, Honda cars (and Goldwings) have required their proprietary silica free coolant. This will probably come down to personal preference - as long as you use a silica free anti freeze you are probably ok. But since you only add a little coolant now and then and replace it fairly infrequently, weigh the cost of a new water pump and peace of mind against using the Honda product. I'm not sure about warranty issues, but most of us are well out of the warranty period.

 

[dduelin]

Most popular brands of automotive coolant have been boron and silicate free for a long time. Just look at the labeling on
the jug. The revolution came along with aluminum engine blocks and ceramic pump seals which once rare are now the norm.

 

[Al st1100]

just use extended life coolant, there is still the old stuff out there. Extended life coolant will intermix with all coolants, bmw, benz and Honda.

 

[Al st1100]

http://prestone.com/corguard_inhibitor_technology

 

[Al st1100]

Can I use extenders in place of SCAs and vice versa with Prestone[SUP]?[/SUP] Heavy Duty Extended Life Antifreeze/Coolant?
A:Both SCA and Extender are used to supplement engine coolants to provide a fully formulated heavy-duty (HD) coolant. However, SCAs and Extenders are as different as conventional silicated HD coolant is to Extended Life HD coolants. SCA chemistry is typically based on a combination of nitrite and inorganic corrosion inhibitors, while Extenders are typically based on nitrite and organic corrosion inhibitors. The use of SCAs in Extended Life coolants or extenders in silicated formulations will negate the benefits of the additive and could jeopardize the cooling system’s life