GM Metro/Sprint 1985-1993 Repair Guide

Fuel and Engine Oil Recommendations



See Figure 1

Use ONLY SG or SG/CD rated oils of the recommended viscosity. Under the classification system developed by the American Petroleum Institute, the SG rating designates the highest quality oil for use in passenger vehicles. In addition, oils labeled Energy Conserving or Fuel Saving are recommended due to their superior lubricating qualities (less friction - easier engine operation) and fuel saving characteristics.

Pick oil viscosity with regard to the anticipated temperatures during the period before your next oil change. Using the accompanying chart, choose the oil viscosity for the lowest expected temperature. You will be assured of easy cold starting and sufficient engine protection.

Click image to see an enlarged view

Fig. Fig. 1: Recommended viscosity grades


Your vehicle is designed to operate on unleaded fuel. Fuel should be selected for the brand and octane which performs best with your engine. Judge a gasoline by its ability to prevent spark knock (pinging) and general all-weather performance.

Use of a fuel too low in octane will result in spark knock (pinging). Since many factors affect operating efficiency, such as altitude, terrain, air temperature and humidity, knocking may result even though the recommended fuel is being used. If persistent knocking occurs, it may be necessary to switch to a slightly higher grade of fuel. Continuous or heavy knocking may result in engine damage.

Fuel requirement can change with time, due to carbon buildup in the engine, which changes the compression ratio. If your engine knocks, pings or runs on, switch to a higher grade of fuel and check the ignition timing. Sometimes changing brands of gasoline will cure the problem. If it is necessary to retard the timing from specifications, don't change it more than a few degrees. Retarded timing will reduce the power output and the fuel mileage, plus it will increase the engine temperature.