That is true. Back at the GM dealer in the Late 70's to the mid 80's, we had a ton of oil consumption issues. We had Pennzoil on tap. We switched to Northland, a local refinery, and within a oil change or two the consumption issues went away. I think Pennz got a bad rep with their paraffin based oils and short trip driving. Wow what a gooey sludge mess under the valve covers and in the valley.
