C8.3 Commercial Marine and Ind [...] Coolant Recommendations and Specifications Section V - Maintenance Specifications Page V-13 Coolant Recommendations and Specifications Fully Formulated Coolant/Antifreeze Cummins, Inc. recommends using either a 50/50 mixture of high-quality water and fully formulated antifreeze or fully formulated coolant when filling the cooling system. The fully formulated antifreeze or coolant must meet TMC RP 329 or TMC RP 330 specifications. CAUTION High-quality water is important for cooling system performance. Excessive levels of calcium and magnesium contribute to scaling problems, and excessive levels of chlorides and sulfates cause cooling system corrosion.