In this retrospective episode, we take a look at used oil analysis, it's beginnings at the turn of the 20th century, and how it changed through the years. You'll learn there are some firm beliefs that have carried over though the years (like when to change the oil and why), as well as the test methods/practices that have coincided with complete paradigm shifts in how we look at oil and its capabilities. You'll also hear another catch pan segment featuring questions on magnetic drain plus and oil consuption on the highway versus in-town driving.