on the one that was done twice initial dose (old instructions) was 500 (Amsoil)with a 1500 mile rinse Penzoil YB the second one was 1500 miles clean with chevron dino and 1500 mile rinse with same. Other vehicle was 1500 and 1500 I believe. Also cut open the filters on these runs and saw nothing of significance. Both vehicles were arouond 100,000 when done.