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.