i recently found out on a tractor forum that rotella t 15w40 conventional has been reformulated and there are two versions. the version found at walmart is the new one and meets certain new standards but there are arguments that the old version is better, especially for older engines.
this is strictly a tip for canadians who want to runa 0w40. I have not been able to get 0w40 synthetic mobil 1 except special ordered from esso in 1 litre bottles in cases of 24 but I have found that the Crappy Tire in north vancouver stocks Shell Rotella full synthetic 0w40 at $30 for 4...