That being said, many Duramax owners find success with high-quality oils meeting or exceeding these specifications. These often include:
* Mobil Delvac 1300 Super: A popular choice known for its performance and protection.
* Shell Rotella T6: Another widely recommended option, especially in colder climates, due to its good cold-weather performance. It's a full synthetic.
* Amsoil DEF Diesel Oil: A premium synthetic oil known for its long drain intervals.
Important Considerations:
* Viscosity: The owner's manual will specify the recommended viscosity grade (e.g., 5W-40, 10W-30, 15W-40). Using the incorrect viscosity can lead to poor performance and engine damage.
* API Certification: Ensure the oil meets the API CK-4 or CJ-4 specification (depending on your engine's year). These are designed for modern diesel engines and offer better protection.
* Synthetic vs. Conventional: Synthetic oils generally offer better performance at both high and low temperatures, along with longer drain intervals. However, they are also more expensive.
* Climate: In colder climates, a 5W-40 or 0W-40 might be preferable for easier cold starts. In warmer climates, a 15W-40 might be sufficient.
In short: Don't just rely on opinions; always refer to your Duramax's owner's manual for the manufacturer's specific oil recommendations. Choosing an oil that meets or exceeds these specifications from a reputable brand will ensure optimal performance and longevity for your engine.
