The 2018 BMW X5 equipped with the 4.4L N63B44B B twin-turbo V8 engine represents the pinnacle of luxury performance utility vehicles, but its complex powertrain demands a level of fluid care that conventional products simply cannot provide. Maintaining the precise tolerances of this high-output engine requires synthetic lubricants that can withstand extreme thermal loads, resist thermal runaway in the transmission, and protect against the unique wear patterns common to turbocharged German engineering. Using the wrong viscosity or chemical composition can lead to premature component failure, increased oil consumption, and a significant drop in fuel economy. This guide outlines the exact AMSOIL products, fluid capacities, and specifications needed to ensure your vehicle operates at peak performance for years to come.
Recommended AMSOIL Products
- AMSOIL 0W-30 MS 100% Synthetic European Motor Oil – The premier choice for this BMW, designed with a unique formula to meet the strict requirements of European engines, providing exceptional protection against high-temperature wear.
- WIX Oil Filter – A high-performance filtration component that offers superior media density to trap contaminants, ensuring the longevity of the oil and engine internals.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Specifically formulated to withstand the rigors of the 8-speed GA8HP75Z transmission, offering enhanced protection during heavy towing and high-performance driving.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – An economical alternative that still delivers premium synthetic protection, ensuring smooth shifting and reduced friction in the automatic transmission.
- AMSOIL SEVERE GEAR® 75W-90 100% Synthetic Gear Lube – Essential for the rear differential, this fluid contains friction modifiers for limited-slip differentials and protects against rust and corrosion while controlling operating temperatures.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Offers superior boiling points and stable viscosity, ensuring crisp pedal response and safety for your BMW’s advanced ABS and traction-control systems.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A pre-mixed 50/50 formula that provides protection up to 150,000 miles or 5 years, safeguarding all cooling system metals and hoses from corrosion.
Engine Oil and Filter Specifications
Proper lubrication for the 2018 BMW X5’s 4.4L V8 is critical. The engine requires a specific viscosity to maintain oil pressure across the vast range of operating conditions the twin-turbochargers impose on the internal components. The recommended oil grade is 0W-30, suitable for all temperatures. The total capacity for a complete oil change, including the filter replacement, is 10.0 quarts. It is crucial to refill the oil and then check the level using the electronic dipstick or gauge in the instrument cluster to ensure accuracy. The oil drain plug must be torqued to 18 ft-lbs, and the drain plug seal should always be replaced to prevent leaks. For filtration, the WIX Oil Filter is the recommended component, offering a premium media construction that outperforms standard OEM units in trapping fine soot and metal particles.
Transmission and Drivetrain Fluids
The X5 is powered by an 8-speed automatic transmission (GA8HP75Z) that shifts with lightning precision but requires specific fluid properties to maintain its smooth operation. A total fill for this transmission is 9.2 quarts. AMSOIL offers two excellent options depending on your budget and needs. The Signature Series Fuel-Efficient Fluid is ideal for those seeking the absolute maximum in thermal stability and extreme wear protection, particularly if you plan to tow heavy loads or drive in hot climates. Alternatively, the OE Fuel-Efficient Fluid provides robust synthetic protection at a value-oriented price point, ensuring the transmission gears and clutches are well-lubricated without compromising on performance.
The rear differential, particularly if equipped with a limited-slip mechanism (QMVH), requires specialized gear lube. The left-side rear differential capacity is 1.1 pints, while the right side requires 1.3 pints. AMSOIL SEVERE GEAR® 75W-90 is the ideal choice here. Its advanced additive package controls thermal runaway, a common issue in high-performance differentials, and the friction modifiers ensure the limited-slip clutch plates engage correctly for optimal traction.
Cooling and Brake System Maintenance
Cooling capacity for the 2018 BMW X5 is 15.7 quarts. Keeping the engine at the correct temperature is vital for the longevity of the twin-turbochargers and the engine block itself. AMSOIL Passenger Car & Light Truck Antifreeze & Coolant is a phosphate, nitrate, and silicate-free ethylene glycol solution that is compatible with all other coolant colors. It protects against rust, corrosion, and hose degradation for up to 150,000 miles. For those who prefer mixing their own, the Concentrated Propylene Glycol Antifreeze offers extended protection, particularly in severe service environments.
Brake fluid is the lifeblood of your safety system. The BMW X5 requires a DOT 4 fluid, and AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid exceeds OEM standards. It prevents moisture absorption, which can lead to brake fade and corroded calipers, while ensuring rapid ABS response and consistent pedal feel in both wet and dry conditions.
About the Vehicle
The 2018 BMW X5, built on the fourth generation of the popular luxury mid-size crossover SUV, strikes a rare balance between spirited driving dynamics and practical utility. Powered by the formidable N63B44B twin-turbocharged 4.4-liter V8 engine, this vehicle delivers robust horsepower and torque figures that rival many sports sedans. The platform, developed on the CLAR architecture, offers a sophisticated suspension system that can be tuned for comfort or sportiness, allowing the driver to switch between “Sport,” “Comfort,” and “Eco Pro” modes to adapt the vehicle’s character to the road ahead. Inside, the cabin is a sanctuary of German engineering, featuring high-quality leather, advanced infotainment systems, and a layout designed to minimize driver fatigue during long highway cruises.
Owners of the X5 appreciate its versatility. It serves as a capable daily driver that can transport a family and their luggage with ease, yet possesses the chassis balance to navigate winding roads with confidence. The N63 engine, a staple in AMSOIL‘s lineup for nearly two decades, is known for its smooth power delivery and distinctive exhaust note. However, this high-performance engine also introduces specific challenges that standard maintenance routines often overlook.
One of the most significant issues facing owners of this specific engine is carbon buildup on the intake valves. Direct Injection (GDI) technology, while efficient, can lead to carbon deposits that restrict airflow and degrade performance over time. Using an AMSOIL P.i.® Performance Improver periodically can help mitigate this issue, restoring horsepower and fuel economy by cleaning the fuel injectors and combustion chamber. Another common concern with the N63 engine is oil consumption, which can be a point of frustration for owners watching the dipstick drop. The high-silicate content in many conventional oils can contribute to this, whereas AMSOIL MS European Motor Oil is formulated to minimize oil consumption while maintaining superior film strength.
Thermal stress is another enemy of the X5’s high-revving powertrain. The twin-turbochargers generate immense heat, which can lead to oil breakdown and eventual failure if the fluid cannot handle the thermal load. AMSOIL synthetic fluids maintain their viscosity and protective properties at higher temperatures than conventional oils, significantly reducing the risk of thermal runaway in the engine and transmission. Additionally, the X5’s rear differential can suffer from clutch chatter or wear if the gear fluid loses its friction-modifying properties. Switching to a dedicated synthetic gear lube like AMSOIL SEVERE GEAR ensures that the limited-slip differential continues to engage smoothly, preserving the integrity of the drivetrain. Finally, the complex electronic brake systems in the X5 rely heavily on the integrity of the brake fluid; synthetic formulations prevent the boiling and moisture absorption that can compromise braking performance, ensuring that this luxury SUV remains safe and responsive in every driving situation.