He thought he was taking good care of the engine. This is an excellent example of what can happen if you don't change your oil as required in your service manual. You may have seen commercials on TV from different oil companies boasting that their oil can work well beyond the change point suggested in your Auto Service Manual. In reality, they have just boosted the oils performance to where it should have been in the first place. Just look at the sludge deposits on the engine block.

The truth is, oil breaks down very quickly if you run it longer than suggested in your Auto Service manual, and should be changed no matter who's oil you use. Exxon Superflo can keep this heartache from happening to you.