MAINTENANCE SECTION 2 Page 37 FAN HUB (BELT DRIVEN) Every 6,000 hours or 3 years, measure the pulley flange end clearance. The end clearance must be 0.08 to 0.41mm [O.O03 to 0.016-inch]. If the end clearance does not meet the above specifications, it musf be rebuilt or replaced. Refer to the Troubleshooting and Repair manual for replacement procedures. COOLANT COOLANT CHANGE AND FLUSHING THE SYSTEM Heavy duty diesel engines require a balanced coolant mixture of water. antifreeze, and supplemental coolant additiws (supplemental coolant additive recommendations are included in this Section). Drain and replace the mixiure every 2 years, or 6,000 hours of operation, whichever occurs first.
In climates where the temperature is above -37°C [-34”F], use a coolant mixture that contains 50 percent antifreeze. Antifreeze is essentia: in any climate. It broadens the operating temperature range by lowering the coolant freezing point and by raising its boiling point. Do not use more than 50 percent antifreeze in the mixture unless additional freeze protection is required. Never use more than 68 percent antifreeze under any condition. DC&i is recommended for use in all Cummins engines.
Use low silicate antifreeze which meets Engineering Standard GM 6038-M or which contains no more than 0.1 percent anhydrous a!!& metasilicate and meets either Engineering Standard GM 1825-M 1699-M which are performance specifications. Use soft water in the coolant mixture. Contaminants in hard water neutralize the corrosion inhibitor components. Water must net exceed 300 ppm hardness or contain more than 100 ppm of either chloride or sulfate. Maintain supplementai coolant additive levels at 1 unit DCA4 per 3.6 liters [l U.S. gallon] of coolant. 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 dupf diesel engine. Supplemental corrosion protection must be supplied through periodic additions of supplemental coclant additives to the coolant. QCA4 UNIT ~A~~T~~ANCE GtJiDE To Protect against corrosion, a new coolant charge must be brought up to 0.26 DCA4 unit per liter [one unit per U.S. gallon] of coolant (initial charge), Maintain the correct DCA4 concentration by changing the maintenance coolant filter at each oil drain interval. Each time the coolant is drained and replace, the coolant must be recharged with supplemental coolant additives. Use the appropriate DCA4 spin-on filter listed in Table 1.
The mixture must be drained and reolaced every 2 years. or 6,000 hours of operation. The amount of replacement inhibitor is determined by the length of the service interval and the cooling system capacity. Refer to the DCA4 Maintenance Guide for the selection of the correct filter to replenish the DCM. If coolant is added between drain intervals. additional DCA4 will be required. Check the coolant periodically just before changing the coolant filter to make sure that the correct maintenance coolant filter is being used. The DCA4 concentration must not fall below 0.13 units per liter or exceed 0.5 units per liter [0.5 units per U.S. gallon nor exceed 2 units per U.S. gallon].