Ford cautions about the use of tap water when final flushing the cooling system of a 6.0L or 6.4L diesel engine in 2003-2010 F-Super Duty trucks. The use of tap water in some geographic areas can lead to unacceptable scaling and/or corrosion within the cooling system (water jackets/passages) as well as decreased coolant pump life.
Prior to using available tap water for the final flush of the cooling system, verify the water quality using water quality test strips, available as Rotunda P/N 328-00007.
1. Collect about 8 oz. of tap water in a clean cup. Water sample temperature must be between 50 and 130 degrees Fahrenheit.
2. Remove a test strip from the foil sealed packet. Do not touch the pads at the end of the strip.
3. Dip the strip in the water sample for 5 seconds, using a gentle back/forth motion. Remove the strip and shake briskly to remove excess liquid.
4. 25 seconds after dipping the strip, compare the pads with the color chart included in the test kit in the following order and record the results:
- Hardness level (end pad)
- pH level (middle pad)
- Chloride level
5. If the tap water does not meet the pass criteria for hardness, pH and chloride, one of the following alternatives should be used for the final flush:
- Distilled water
- Deionized water
- Purified water from a reverse osmosis water filter system