Coolant Recommendations?

[Oldscoot]

Has anyone topped off or changed the coolant?  If so, what brand of antifreeze did you use? With my Vespa I use Dex antifreeze and it is compatible with the factory fluid.  Using the wrong stuff can result in sludge being formed and problems with water pump wear.  Thanks in advance.

     

[old geezer]

My Kymco dealer uses Pro Honda HP coolant 50/50blend to top up the Kymcos in their shop. I bought a quart to top up my People S 250. Its the same color as whats in there. I have had no problems.

Be careful with Dex cool. Its not compatible with every thing our there.

[Oldscoot]

My Kymco dealer uses Pro Honda HP coolant 50/50blend to top up the Kymcos in their shop. I bought a quart to top up my People S 250. Its the same color as whats in there. I have had no problems.

Be careful with Dex cool. Its not compatible with every thing our there.

Thanks for the recommendation.  You're right about Dex in some applications.  However, I believe it was formulated by the Euro-American joint venture and is good for aluminum engines.  The original Vespa fluid is pink and not compatible with some other coolants. Although color may not be a determinant -- like the red-yellow-black banding of a coral snake it's a good heads up.     

[old geezer]

Dex-cool is very good for aluminum engines. It just does not play well with other coolants. Although the latest version is supposed to be better.

 I believe Japanese P-OAT coolant technology is just as good for aluminum engines and may play better with other coolants. never mix the old green coolant with any of the newer coolants.

Also do not use coolants with silicate inhibitors to protect against aluminum corrosion as they are abrasive and will wear out the water pump seal. The Honda HP coolant is silicate free. It has other inhibitors that are silicate free to protect aluminum engines.

[Vivo]

OAT / Diethylene Glycol has a higher boiling point and is also longer lasting than your usual green Ethylene Glycol coolant. Old G. is right on the silicates. Silicates is ok when new but you have to change it after a year or so otherwise they solidify into a white sandy substance that will clog and destroy your water pump/radiator. However, ethylene glycol based coolants (green) are best for very cold countries because it's freezing point is lower at -40 or lower degrees celsius versus diethylene glycol's -8 degrees celsius. Also, don't be fooled with the coolant colors. They use a lot of different colors nowadays. Glycols are colorless and they just use dye to color coolants for identification purposes. Color is also essential in detecting leaks.  Read the label to make sure of the ingredients. I usually don't buy premix because you're paying for (50%) water. I buy pure/concentrated coolants and mix with distilled drinking water.