The 2018 GMC Terrain requires Dexos1 Gen 2 engine oil, typically in a low-viscosity grade such as 0W-20 or 5W-30, depending on the engine option and climate. Always verify the exact specification in your owner's manual or with a GMC dealer.
Official specification and viscosity guidance
GMC/GM specifies Dexos1 Gen 2 as the required oil standard for the 2018 Terrain. The exact viscosity your engine uses depends on the installed engine and local climate, so it’s important to confirm the recommendation for your model year and configuration.
Below are the main approved options and considerations.
- Dexos1 Gen 2 certified engine oil is required. Oils that do not meet this specification should not be used.
- Approved viscosities often include 0W-20 and 5W-30; the exact grade depends on the engine variant and climate.
- Oil can be conventional, synthetic-blend, or full synthetic, provided it is Dexos1 Gen 2 compliant.
- Choose a reputable brand and check the bottle for the Dexos1 Gen 2 certification mark and the viscosity on the label.
- Follow GM’s recommended oil-change intervals for the 2018 Terrain, which vary by oil type and driving conditions.
In practice, the recommended approach is to use Dexos1 Gen 2 oil in the correct viscosity for your engine and climate, and to adhere to the maintenance schedule to maintain warranty coverage and engine health.
Which oil to choose by engine variant
There were two common engine options for the 2018 Terrain. The oil specification remains Dexos1 Gen 2, but the viscosity guidance can differ by engine and temperature range. The following sections outline the general guidance for each engine family and what to check in your manual.
2.4L Ecotec inline-four
For the 2.4L engine, GM typically recommends Dexos1 Gen 2 oil in a low-viscosity grade suitable for year-round operation in most climates. Check the owner’s manual for the exact grade recommended for your region, as it may specify 0W-20 or 5W-30 depending on climate and usage.
2.0L Turbo
The 2.0L turbo may have slightly different viscosity guidance; however, it remains Dexos1 Gen 2 compliant. The manual will specify the precise grade, but many owners use 0W-20 or 0W-30 in moderate climates and 5W-30 in hotter regions.
How to verify and maintain the correct oil
To ensure you’re using the correct oil for your Terrain, use the following verification steps before each oil change.
- Consult the 2018 Terrain owner's manual for the exact Dexos1 Gen 2 requirement and viscosity for your engine and climate.
- Look for the Dexos1 Gen 2 certification logo on the oil bottle and packaging to ensure compatibility.
- Use a reputable brand that offers Dexos1 Gen 2 compliant oils; synthetic blends and full synthetics are both acceptable as long as they are certified.
- Do not mix oil grades beyond what the manual specifies, and avoid non-Dexos1 oils.
Following these steps helps protect the engine, maintain performance, and preserve warranty coverage.
Summary
In short, the 2018 GMC Terrain uses Dexos1 Gen 2 engine oil, with viscosities such as 0W-20 or 5W-30 depending on the engine and climate. Verify the exact specification in the owner’s manual or with a dealer and choose an oil that is Dexos1 Gen 2 certified. Adhere to GM’s recommended service intervals for the best results.
Summary of the article: The essential requirement is Dexos1 Gen 2 certification; always confirm viscosity for your engine and climate with the manual or dealer. Regular oil changes with the correct oil help maintain engine performance and warranty compliance.