Schaeffer Manufacturing Co. 9004-012S Supreme 9000 Full Synthetic Gasoline Engine Oil 5W-20, 1-Quart Bottle

Customers find this engine oil to be the best they've used, reporting that their vehicles run smoother and experience better fuel economy. They appreciate its performance, with one customer noting it keeps their engine running top-notch. While some customers consider it well worth the money, others find it a bit pricey.