Most GL450 models use a fully synthetic engine oil that meets Mercedes-Benz specification MB 229.5 or 229.51, typically in a 5W-40 viscosity. However, exact requirements vary by model year and engine variant, so verify with your owner's manual or the under-hood label before purchasing oil.
Beyond the short answer, this article explains how to identify the precise oil spec for your GL450, what to buy, and how to confirm compatibility based on climate and maintenance intervals.
Oil specifications: the basics for the GL450
Mercedes-Benz uses spec codes to guarantee an oil is compatible with your engine. For most GL450 gasoline engines, the long-life MB 229.5/229.51 standard is commonly required, with 5W-40 synthetic being the typical viscosity. In very cold climates or for certain model years, 0W-40 or 5W-30 may be approved if the oil also meets the correct MB spec. Always rely on the oil cap label or the owner's manual for the exact specification.
Note: MB updates approvals across model years, so the precise designation can vary, even within the GL450 family.
Here are the common options you’re likely to encounter:
- Most GL450s require fully synthetic oil that meets MB 229.5 or 229.51; a frequent viscosity is 5W-40.
- Some older configurations or climate-specific setups may use 0W-40 or 5W-30 if approved under MB spec 229.3/229.1 or equivalent; always confirm.
- Use only MB-approved oils that carry the 229.x designation to protect engine health and warranty.
In practice, 5W-40 synthetic MB 229.5/229.51 is the standard recommendation for the GL450 across most model years, but verify for your particular vehicle.
How to verify the exact oil spec for your GL450
Because MB specification can shift by year and engine variant, the most reliable confirmation comes from your car’s documentation and on-vehicle labels.
To verify, follow these steps:
- Check the owner’s manual or service booklet for the exact MB 229.x specification required for your engine and year.
- Inspect the oil filler cap on the engine; many Mercedes caps show the MB specification and sometimes the viscosity.
- Review the vehicle’s service sticker or digital service menu for the recommended oil spec and change interval.
- Consult a Mercedes-Benz dealer or trusted independent shop if you’re unsure; provide the exact model year and engine code for precise guidance.
Once you know the correct MB spec, select a fully synthetic oil that carries that approval and use the recommended viscosity for your climate and service plan; this aligns with Mercedes’ maintenance guidelines.
Summary
For most Mercedes GL450 models, the go-to oil is a fully synthetic oil meeting MB 229.5/229.51, typically 5W-40. Exact requirements can vary by year and engine variant, so always check the owner’s manual, the oil cap, or a dealership label to confirm. If you’re in a very cold climate or have a specific MB spec for your year, follow that guidance precisely. Regularly using an MB-approved oil helps protect the engine and maintain warranty coverage.
What is the most reliable year of GLS?
We recommend 2021 and later GLS models, as the second generation represented a marked improvement in performance, interior quality, and style. As usual, it's best to avoid the first model year of any new car generation to swerve issues with early production runs, which are usually ironed out later on.
Can I put 5W-30 in my Mercedes-Benz?
Recommended oil viscosity varies by engine, but common Mercedes-Benz options include 0W-20, 0W-40, 5W-30, and 5W-40. All recent Mercedes-Benz vehicles require fully synthetic oil for optimum performance and engine protection.
What kind of oil does a GL450 take?
7 liters 5W-40 motor oil, oil filter, and hardware for 2015-2016 Mercedes-Benz GL 450 and 2017-2019 Mercedes-Benz GLS 450 3.0L V6 gasoline applications. Oil carries OEM approval for MB 229.5 oil standard and is made in Germany.
What are common GL 450 problems?
- The camshaft adjusters (VVT gears) can fail, throwing timing off and causing misfires. - Turbo coolant lines can leak, leading to slow coolant loss over time. - Turbo oil seals can fail - The PCV system (oil separator) is prone to failure, leading to oil consumption and rough idling.