My second Auto Rx treatment phase ends in two days. I plan to run the rinse for 2000 miles (instructions say 2000 to 3000 miles for second rinse). Then I thought, why not, at the end of the rinse, throw 6 oz Neutra 131 in there (6 qt sump with filter) to give it a final purge, run it 500 more miles, and then drain it out.