Last time at the Cummins Dealer to get oil, oil filter and service coolant filter, I also bought a test strip and chart to read it by. Sort of like testing pool water. I am in good shape. I took the same out of the petcock under the radiator into an emptied water bottle just emptied, and poured the water over the 3 point test strip and shook it and waited 45 seconds as per instructions. freeze point is minus 30. Molybdate is what the chart calls ROW1 and the Nitrite was 1.9. According to the chart, the SCA units per gallon was 1.9 and instructions say to continue to replace service coolant filter with each oil drain interval. This is for a COMPLEAT system which I assume I have since the ES system also shown does not show the filter.

The instructions are specific to get the sample from the petcock below the radiator and not the overflow tank.

Tom Taylor
94 Breakaway XL
44K miles.

In rereading this which I should have done before I posted, I took the sample from the rediator and poured the sample over the test strip and shook the test strip. (then the two step and twist)