there was a girl in the oil isle confused, she picked up a bottle of Genuine 30 wt oil for $.84 cents. She asked a walmart employee who was passing by if it was okay for a lawnmower that needed 30 weight. the walmart employee said yes and she put the bottle in her basket. When the walmart employee left, I said "you don't want that oil in your lawnmower" So she asked me about it, I pointed out that it was non-detergent. to make the long story short, she picked up a bottle of Pennzoil straight 30 weight for her lawn mower. It is obvious her husband or boyfriend told her to pick up a bottle of 30 wt for the lawnmower. She almost made a drastic mistake! After she left, I looked at the back of Genuine 30wt non detergent SA oil. "Caution: Do not use in automotive engines built after 1930"