MAINTENANCE Coolant Testing for Conditioner Concentration When the cooling system is maintained as recommended, the conditioner concentration should be satisfactory. The SCA concentration must not fall below 1.0 unit per 3.8 only accurate method for testing chemical concentrations in coolant with mixed chemical compounds is a laboratory analysis. For this reason, the coolant inhibitor should be maintained as shown in 23.1 on page 3-26 . NOTE: 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 restriction, plugging of passages and overheating.
Replenishing Coolant Conditioner Install a "precharge" coolant filter when the coolant is changed or a significant (more than 50%) coolant loss occurs. Install a service coolant filter as specified in ? On page ?-? . When antifreeze is added, add coolant conditioner equal to 1.0 unit per 3.8 NOTE: Mixing of DCA4 and other supplemental coolant additives is not recommended because there is currently no test kit available to measure concentration levels with mixed chemical solutions. Supplemental Coolant Additive Maintenance Guide Use supplemental coolant additives (corrosion inhibitors) to protect the engine cooling system from corrosion.
Antifreeze alone does not provide enough corrosion protection for a heavy duty diesel engine. Supplemental corrosion protection must be supplied through periodic additions of supplemental coolant additives to the coolant. To protect against corrosion, a new coolant charge must be brought up to 0.26 SCA unit per liter [one unit per U.S. gallon] of coolant (initial charge). Maintain the correct SCA concentration by changing the service coolant filter at each engine oil and filter change interval. Each time the coolant is drained and replace, the coolant must be recharged with supplemental coolant additives. Use the appropriate replacement coolant filter listed in following tables.
The coolant mixture must be drained and replaced as defined under "General.” The amount of a replacement inhibitor is determined by the length of the service interval and the cooling system capacity. Refer to the DCA4 Unit Guide for the selection of the correct filter to replenish the SCA. If coolant is added between drain intervals, additional SCA will be required. Check the coolant DCA concentration level anytime make up coolant is added to the system. The SCA concentration must not fall below 0.13 units per liter or exceed 0.5 units per liter [0.5 units per U.S. gallon or exceed 2 units per U.S. gallon]. 3-17 WA320-3MC