Generally, for a 5.7L V8 in a Lumina (assuming it's a generation that used this engine; they weren't all 5.7L), you'd be looking at oil viscosities such as:
* 5W-30: This is a common and versatile viscosity for many vehicles, suitable for a wide range of temperatures. It's often a good starting point if your owner's manual doesn't specify.
* 10W-30: This is another common viscosity, generally better suited for warmer climates.
Regarding oil type:
* Conventional: The most affordable option, but generally offers less protection and doesn't last as long as synthetics.
* Synthetic Blend: A compromise between conventional and full synthetic, offering better performance than conventional at a lower price than full synthetic.
* Full Synthetic: The most expensive option, but it offers the best protection, longevity, and performance, especially in extreme temperatures.
API Certification: Look for an oil that meets the API (American Petroleum Institute) certification recommended in your owner's manual. This ensures the oil meets minimum quality standards.
In short: Consult your owner's manual. It's the single best source of information for the specific oil requirements of your 1990s Chevrolet Lumina 5.7L V8. Using the wrong oil can severely damage your engine.
