The 2012 Mercedes-Benz GL350, equipped with the robust 3.0L 6-cylinder diesel turbo engine (Code 642.820 J), represents a pinnacle of German engineering designed for both on-road luxury and off-road capability. However, the sophisticated architecture of this diesel powertrain demands a level of fluid purity and protection that traditional conventional lubricants simply cannot provide. Because this engine features high-precision components like a turbocharger and a high-pressure fuel injection system, it operates under extreme temperatures and significant thermal stress. Maintaining optimal performance and longevity requires fluids that exceed original equipment manufacturer (OEM) specifications, ensuring that critical components such as bearings, gears, and seals are properly lubricated and protected against wear, sludge, and corrosion.
Recommended AMSOIL Products
- AMSOIL 0W-30 MS 100% Synthetic European Motor Oil – Specifically formulated for the precise demands of European diesel and gasoline engines, providing superior protection against turbocharger damage.
- MANN-FILTERS Oil Filter – A premium filtration system featuring high-grade media that offers improved particle capture compared to standard OEM filters.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Designed to withstand the rigors of heavy towing and elevated temperatures while maintaining fluidity in sub-zero conditions.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A unique poly-OAT formulation that exceeds OEM requirements and provides protection for up to 150,000 miles or 5 years.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Ensures excellent responsiveness for ABS and traction control systems with stable viscosity across a wide temperature range.
- AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid – Helps seals remain soft to prevent leaks while providing strong anti-wear protection for long fluid life.
Maintaining the correct fluid levels and types in your 2012 GL350 is not just about adhering to a maintenance schedule; it is about preserving the vehicle’s complex engineering. The 3.0L OM 642 diesel engine, known for its torque and efficiency, generates substantial heat that can break down standard mineral oils quickly. By switching to a high-quality synthetic motor oil like the AMSOIL 0W-30 MS 100% Synthetic European Motor Oil, you ensure that the engine receives a consistent film of lubrication even during the initial startup in cold weather or the intense heat of extended towing. The 0W-30 viscosity grade is optimal for all temperatures, while 0W-40 is also recommended for varying conditions, ensuring that the turbocharger shafts and bearings are always protected from wear.
Engine Oil and Filtration Requirements
The heart of the GL350’s maintenance routine is the engine oil change. This vehicle requires a substantial amount of fluid due to its large displacement and the inclusion of a spin-on filter. The engine oil capacity is 9.0 quarts when changing both the oil and the filter. It is crucial to refill the correct amount and then check the oil level immediately after the engine has been refilled. For the oil drain plug, a specific torque of 33 ft/lbs is required for the 24 MM plug to ensure a proper seal without damaging the threads.
In conjunction with the oil, filtration is paramount. The recommended filter for this vehicle is the MANN-FILTERS Oil Filter. This filter utilizes premium media that outperforms original equipment manufacturer-branded filters in capturing harmful contaminants. By trapping abrasive particles that can cause premature wear on pistons, cylinders, and the turbocharger, this filter extends the life of the oil and the engine itself. Using a filter designed specifically for the high-flow demands of this diesel engine is essential for maintaining peak efficiency.
Transmission and Drivetrain Fluids
The GL350 is equipped with a 7-speed automatic transmission that demands a high-performance fluid to handle the torque output of the diesel engine. The transmission specifications indicate a total fill capacity of 9.5 quarts for the 7-speed 722.9 transmission. It is important to note that the vehicle may come with or without the A89 reduced-friction code. In either case, the fluid must provide excellent frictional stability to prevent shudder and ensure smooth shifting. The AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid is ideal for this application, offering protection against wear and remaining fluid even in sub-zero temperatures.
For those seeking a more cost-effective option that still meets high standards, the AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid is a viable alternative. Both fluids are designed to protect the transmission from wear, sludge, and temperature-related issues, which are common problems in high-mileage diesel vehicles. The transfer case and differential fluids are also critical. For the transfer case, the capacity varies by configuration: double speed requires 3.2 pints, while single speed requires 1.1 pints. The front differential capacity is 2.3 pints. While the source data highlights transmission fluid recommendations for these areas, using a high-quality synthetic fluid ensures that the gears and bearings within the drivetrain remain lubricated and protected from the harsh conditions the GL350 may face.
Cooling System and Fluid Maintenance
Proper thermal management is vital for the longevity of the GL350’s engine. The cooling system capacity is 10 quarts. Maintaining the correct AMSOIL Passenger Car & Light Truck Antifreeze & Coolant mixture prevents corrosion, freezing, and boiling, which can lead to catastrophic engine failure. AMSOIL offers two primary options for the GL350: the AMSOIL Passenger Car & Light Truck Antifreeze & Coolant, which comes as a 50/50 pre-mix in a convenient gallon jug, and the AMSOIL Propylene Glycol Antifreeze and Engine Coolant, a concentrated formula that allows for precise mixing with distilled water. Both fluids are engineered to exceed OEM requirements and are free from phosphates, nitrates, and silicates, making them safe for all cooling system metals, gaskets, and hoses.
AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid is another often-overlooked component that requires attention. The GL350 requires a DOT 4 plus fluid, specifically products approved on Mercedes-Benz Sheet 331.0. AMSOIL’s AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid is an excellent choice, offering excellent responsiveness for anti-lock braking systems (ABS) and traction control. Its stable viscosity over a wide temperature range ensures consistent pedal feel and braking performance, which is critical for a vehicle of this size and weight.
AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid also benefits from synthetic maintenance. The recommended fluid for this vehicle is the AMSOIL 100% Synthetic Multi-Vehicle Power Steering Fluid. This fluid is formulated to reduce friction, help seals remain soft to prevent leaks, and resist heat for long fluid life. It provides strong anti-wear protection and excellent high-temperature performance, ensuring quiet operation and responsive steering for the owner.
About the Vehicle
The 2012 Mercedes-Benz GL350 is a significant chapter in the history of the German luxury SUV market. Based on the ML-Class platform, the GL350 was introduced as a more spacious and luxurious variant, offering a unique blend of on-road refinement and off-road prowess. Under the hood lies the 3.0L V6 turbo-diesel engine, a powerhouse known for its low-end torque and exceptional fuel efficiency compared to its gasoline counterparts. This engine, part of the OM 642 family, has become legendary for its durability and engineering excellence.
Owners of the GL350 appreciate its commanding road presence and the high-quality interior that defines the Mercedes-Benz brand. The vehicle typically seats up to seven passengers, making it a versatile choice for families and adventure enthusiasts alike. Its advanced 4MATIC all-wheel-drive system provides confidence in various weather conditions, allowing drivers to tackle challenging terrain with ease. The suspension is tuned to balance comfort with the handling dynamics expected of a luxury crossover, though its true strength lies in its ability to serve as a rugged companion for off-road excursions without sacrificing the ride comfort of a premium sedan. The GL350’s reputation is built on its ability to combine the utility of a truck with the sophistication of a high-end European car, creating a vehicle that is both highly functional and a pleasure to drive.
By utilizing AMSOIL synthetic lubricants, GL350 owners can ensure that this impressive machine continues to perform at its best. The comprehensive range of fluids, from motor oil to brake fluid, is designed to provide maximum protection against the specific stresses encountered by this vehicle. Whether you are driving in extreme cold, towing heavy loads, or simply commuting daily, the use of high-performance synthetic fluids will keep your Mercedes-Benz GL350 running smoothly for the long haul. Regular maintenance with the correct products is the key to unlocking the full potential and longevity of this remarkable vehicle.