The recommended motor oil for a 2000 Chevy S10 with a 4-cylinder engine depends on several factors, but
consult your owner's manual for the most accurate and specific information. The manual will specify the recommended oil viscosity (like 5W-30 or 10W-30) and the API certification (like SM or SN, or potentially even newer certifications now).
Generally, for that year and engine, a 5W-30 or 10W-30 oil meeting the correct API standard would be common choices. However, your owner's manual will provide the definitive answer tailored to your specific vehicle's conditions and recommendations. Using the wrong oil can damage your engine.