Every 6 Years or 6000 Hours

1. 
   BM004697-UN-29FEB16

   
   BM004698-UN-29FEB16

   S660 and S670 Radiator Drain

   
   BM004699-UN-29FEB16

   S680 and S690 Radiator Drain

   A - Drain

   B - Surge Tank

   Radiator - Open drain (A) to remove coolant from radiator.

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2. Surge Tank - Flush and refill with correct coolant and conditioner (see Cooling System—Draining in Service Engine section and Engine Coolant recommendations given in Fuels and Lubricants section). Check engine coolant level in surge tank (B) with engine cold. Level must be up to Max Cold line.

   IMPORTANT: Water quality is important to the performance of the cooling system. Distilled, deionized, or demineralized water is recommended.