GM: Electra/Park Avenue/Ninety-Eight 1990-1993

Fuel and Engine Oil Recommendations


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Fig. Fig. 1 Engine oil viscosity recommendations

It is important to use fuel of the proper octane rating in your car. Octane rating is based on the quantity of anti-knock compounds added to the fuel and it determines the speed at which the gas will burn. The lower the octane rating, the faster it burns. The higher the octane, the slower the fuel will burn and a greater percentage of compounds in the fuel prevent spark ping (knock), detonation and preignition (dieseling).

Using leaded gasoline can damage the emission control system by decreasing the effectiveness of the catalyst in the catalytic converter and by damaging the oxygen sensor which is part of the engine management system. Unleaded gasoline only must be used in your vehicle to prevent damage to these components.

Do not use gasoline containing more than 5 percent methanol even if they contain cosolvents and corrosion inhibitors.

All engines are designed to use only unleaded gasoline, with a Research Octane Number (ron) rating of at least 91, or an Antiknock Index of 87. Higher octane fuels will help keep your fuel system cleaner and may add some performance.

Engine oils are labeled on the containers with various api (American Petroleum Institute) designations of quality. Always use sg quality energy conserving oils of the proper viscosity. The oil with quality designation sg, will protect the engine better than the previous oils. The sg designation may be shown alone or in combination with other designations such as sg/cc, sg/CD, sf, sg or cc.

Engine oil viscosity (thickness) has an effect on fuel economy and cold weather starting. The lower viscosity oil can provide better fuel economy and cold weather performance, but if used in hot weather condition, may not provide adequate engine lubrication. 5W-30 or 10W-30 are the only viscosities recommended for your engine at any temperature range.

Using oils of any viscosity other than those recommended may cause engine damage.

When choosing an engine oil, use a well-known name brand, and consider the range of temperature the vehicle will be operated in before the next oil change. Refer to the `Engine Oil Viscosity Recommendations' chart in this section.