My truck goes through about 1 quart every 200 miles. During the cleaning cycle of the auto rx treatment, when I need to add oil, do I add more auto rx with the oil? Obviously I can't go the 1500 miles without adding any motor oil.
No, just add your make up oil. If additional cleaning is required, do another round after the cleaning phase. That is, start a new treatment after completing the first.
Just a tip if your 7.3 uses much oil: Try to clean or replace the crankcase ventilation box, looks like a tuna can sitting on the back of the air intake under the filter housing. Remove it and flush it with kerosene and check that the small pinhole is open and that the membrane inside is intact/not leaking.
