Owner Manual
Page 384
... The cap must be used up to 5 Years or 100,000 miles before replacement. The cap should be fully tightened to prevent loss of coolant, and to insure that you use of corrosion protection in the area where the vehicle is operated. To prevent reducing this extended maintenance... material on the sealing surfaces. Use only high purity water such as distilled or deionized water when mixing the water/engine coolant solution. This coolant can be inspected and cleaned if there is any accumulation of protection against freezing according to the temperatures occurring in the engine...
... The cap must be used up to 5 Years or 100,000 miles before replacement. The cap should be fully tightened to prevent loss of coolant, and to insure that you use of corrosion protection in the area where the vehicle is operated. To prevent reducing this extended maintenance... material on the sealing surfaces. Use only high purity water such as distilled or deionized water when mixing the water/engine coolant solution. This coolant can be inspected and cleaned if there is any accumulation of protection against freezing according to the temperatures occurring in the engine...