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What Cummins Marine Diesel Engine Coolant Should I Use?

Fleetguard ES Compleat EG Premix 50/50 1 GalThe only answer I can give you is to see if the coolant meets Cummins requirements for a low silicate coolant… Most ELC’s that I have seen are “Dexcool” spec, meaning no silicates and some other things, and at this time I do not believe Cummins wants them used in the mid-range engines. But, on the other hand, the B’s and C’s are not super sensitive to coolant make-up, unlike Yanmar and possibly some others are, so I really doubt it would matter. Why not just go 3-4 years on your other coolant if hours are low per year–or, why not just run a $3 test every year instead of just changing it????

Unless you know you have gunk in there, just use and re-fill with a name brand 50/50 EG-based coolant. The B’s and C’s are not as coolant sensitive as many other engines are.

On the 8.3 & 8.9, and M-11’s use a coolant filter that has the DCA additive you need for the liner-ed engine.