For diesel engine vehicles, see “Engine Oil” in the Duramax Diesel Supplement.

To ensure proper engine performance and long life, careful attention must be paid to engine oil.

Following these simple, but important steps will help protect your investment:

• Always use engine oil approved to the proper specification and of the proper viscosity grade. See “Selecting the Right Engine Oil” in this section.

• Check the engine oil level regularly and maintain the proper oil level. See “Checking Engine Oil” and “When to Add Engine Oil” in this section.

• Change the engine oil at the appropriate time. See Engine Oil Life System on page 10‑10.

• Always dispose of engine oil properly. See “What to Do with Used Oil” in this section.

• Checking Engine Oil
• When to Add Engine Oil
• Selecting the Right Engine Oil
• Specification
• Viscosity Grade
• Engine Oil Additives/Engine Oil Flushes
• What to Do with Used Oil