MAINTENANCE SECTION 2 Page 17 COOLANT ADDITIVE CONCENTRATION * Inadequate concentration of the coolant additive can result in major corrosive damage to cooling system components. Over concentration can cause formation of “gel” that can cause restric- tion, plugging of passages, and overheating. * If the engine coolant is changed, the coolant filters must also be changed. The cooling system must contain the proper coolant additive units to provide the best chemical protection. DCA4 Test Kit: Use only DCA4 Coolant Test Kit, Fleetguard Part No. CC-2600 to check the coolant additive concentration in the cooling system. * Check once every 6 months, regardless of the number of hours operated.