Coolant

[weephee]

I have a 3GM30F Yanmar that's been rebuilt. Can I use the orange Dexcool coolant 50% Thanks

[tkeithlu]

Sure. Coolants are basically ethylene glycol. They raise the boiling point and lower the freezing point, so you can run a bit hotter without spraying stuff all over your boat, and not crack the block in winter. They usually include some rust inhibitors as well. Take your pick, just as you would between engine oisl with particular ratings.

[gonesail]

there is a difference between the yellow and orange .. and you should not mix the 2 together. i like the yellow for my vehicles.

[Paul L]

From MackBoring on Yanmar coolant

The coolant/anti-freezes that have been tested and approved are shown below:
• Texaco Long Life Coolant Anti-Freeze both regular and pre-mixed Product codes 7991 and
7998. This product is available in gallon containers, drums and bulk. It is recommended that the
cooling system be drained and flushed before filling. Only Texaco Long Life Coolant should be
used for top-off. This product has a much longer shelf life than conventional coolants provided
the integrity of the container is maintained. For additional information and availability contact
Texaco at 1-800-782-7852.
• Havoline Extended Life Anti-Freeze/Coolant. Product code 7994. This product is available
through Texaco gas stations, Procedures are the same as with Texaco Long Life Coolant Anti-
Freeze.
• Dex-Cool Long Life Coolant. This product is available through GM service centers worldwide.
• Prestone Extended Life Coolant. Product code AF888. If the above coolants are not readily
available, Prestone Extended life coolant is satisfactory.

[Midnight Son]

Which ever coolant you use. Make sure it is for Diesel engines, as it has compounds that help cut the cavitation that happens on the cylinders/liners, by coating the liners.

On YouTube, you can find a few videos, that show leaking liners, where the wrong coolant was used, and the cavitation eroded the liner enough to cause a coolant leak into the cylinder.

This does not happen quickly, but slowly, progressively.
Change coolant annually on small engines, on larger engines, install/replace the coolant filter annually, and use test strips to ensure/measure protection strength.
Best wishes all.