The 2018 BMW 640xi is a sophisticated vehicle powered by a 3.0L inline-six turbocharged engine. To maintain peak performance and longevity, it requires lubricants specifically formulated to handle the high stresses of turbocharged European engines. Using the correct viscosity and fluid specifications ensures that internal components remain protected against wear, heat, and deposit buildup.
Recommended AMSOIL Products
- AMSOIL 0W-30 MS 100% Synthetic European Motor Oil – A specialized formula designed for the unique demands of European gasoline and diesel engines, providing superior protection against high-temperature deposits and wear.
- AMSOIL Oil Filter – Features a high-efficiency media that captures 99 percent of contaminants at 20 microns, offering greater capacity for small wear-causing particles compared to standard filters.
- MANN-FILTERS Oil Filter – A premium aftermarket alternative that provides high-quality media with improvements over standard original equipment manufacturer filters.
- AMSOIL Passenger Car & Light Truck Antifreeze & Coolant – A ready-to-use 50/50 pre-mix formula that protects against corrosion in all cooling system metals and hoses for up to 150,000 miles.
- AMSOIL Propylene Glycol Antifreeze and Engine Coolant – A concentrated, phosphate-free antifreeze that allows for custom mixing and extended service life of up to 150,000 miles.
- AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – Engineered to withstand the rigors of heavy towing, elevated temperatures, and challenging terrain while remaining fluid in sub-zero conditions.
- AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid – A cost-effective synthetic option that provides reliable protection against wear for the BMW’s 8-speed transmission.
- AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid – Delivers excellent ABS and traction-control responsiveness with a stable viscosity range to prevent boiling under heavy braking.
Why Proper Lubrication Matters for the BMW 640xi
The 2018 BMW 640xi features the N55B30A engine, a turbocharged inline-six that operates under significantly higher thermal and mechanical stresses than naturally aspirated engines. The turbocharger spins at incredibly high speeds, generating intense heat that can degrade conventional oils rapidly. Without proper protection, this heat can lead to sludge formation, varnish buildup on piston rings, and accelerated wear on bearings and camshafts.
Proper lubrication extends the service life of critical components by maintaining a robust oil film even at high temperatures. The 640xi requires a specific viscosity of 0W-30 to ensure rapid flow during cold starts while maintaining adequate film strength during high-temperature operation. Using an oil designed for European vehicles, such as AMSOIL 0W-30 MS 100% Synthetic European Motor Oil, ensures that the additive package is tuned to combat the specific deposit tendencies of German-engineered engines.
Engine Oil and Filtration Specifications
For the 3.0L N55B30A turbo engine, the oil capacity is 6.9 quarts when performing a standard oil change with a filter replacement. After refilling, it is crucial to check the oil level to ensure accuracy. The oil drain plug should be torqued to 18 ft-lbs, and the seal should always be replaced during service. The AMSOIL Oil Filter is the recommended choice for superior filtration, capturing microscopic contaminants that can cause wear. For those who prefer an alternative, the MANN-FILTERS Oil Filter is also a highly rated option that offers premium media for improved engine protection.
Transmission and Differential Care
The 2018 BMW 640xi is equipped with an 8-speed automatic transmission (GA8HP45Z). The total fill capacity for the transmission is 9 quarts. This transmission operates at high temperatures, and maintaining fluid integrity is vital for shift quality and component longevity. AMSOIL Signature Series Fuel-Efficient 100% Synthetic Automatic Transmission Fluid offers maximum protection against wear and sludge, ensuring smooth shifts and extended fluid life. Alternatively, the AMSOIL OE Fuel-Efficient 100% Synthetic Automatic Transmission Fluid provides a robust, fuel-efficient option that meets the necessary specifications for the vehicle.
While the specific differential fluid details for the rear differential are not provided in the summary, it is standard practice for these vehicles to require regular attention to ensure the all-wheel-drive system operates smoothly. Using a high-quality synthetic lubricant designed for BMW differentials can help reduce noise and prevent premature wear in the drive components.
Cooling and Braking Systems
Effective cooling is essential for the 640xi’s turbocharged engine. The cooling system capacity is 10.8 quarts. AMSOIL Passenger Car & Light Truck Antifreeze & Coolant is a convenient 50/50 pre-mix, and the AMSOIL Propylene Glycol Antifreeze and Engine Coolant is a concentrated formula that requires mixing with distilled water. Both options provide excellent corrosion protection for all metals, gaskets, and hoses, with service intervals extending up to 150,000 miles or five years.
Braking performance is critical for a vehicle of this performance class. The 640xi requires DOT 4 Low Viscosity fluid, compatible with BMW P/N 83 13 0 443 024 or 83 13 0 443 026. AMSOIL DOT 3 and DOT 4 100% Synthetic Brake Fluid is formulated to prevent boiling under heavy braking and ensures consistent pedal feel, enhancing safety and control in various driving conditions.
Vehicle Background
The 2018 BMW 640xi represents a significant chapter in the legacy of the BMW 6 Series, specifically the F12/F13 generation. This model is a luxurious grand tourer that blends aggressive performance with high-end comfort, offering a driving experience that is both refined and dynamic. Powered by the robust N55B30A engine, the 640xi delivers a potent mix of power and torque, characteristic of BMW’s commitment to driving dynamics. The “xi” designation indicates that this model is equipped with BMW’s xDrive all-wheel-drive system, providing enhanced traction and stability in diverse weather conditions, making it a viable choice for year-round driving.
Owners of the 640xi often appreciate the car’s ability to serve as a daily driver without compromising on performance. The interior is typically equipped with premium materials, advanced technology, and ergonomic seating designed for long-distance comfort. The vehicle’s stance is athletic, featuring a sleek coupe or convertible body style that has been a favorite among enthusiasts who value both aesthetics and engineering excellence. The 6 Series sits in a unique market position, bridging the gap between the sportier 4 Series and the more utilitarian 5 Series, offering a distinctive blend of luxury and agility.
While the 640xi is a remarkable vehicle, it does share some common challenges typical of high-performance European cars with turbocharged engines. One prevalent issue found in the N55 engine family is oil consumption, where the vehicle may require top-offs between scheduled maintenance intervals. This can be caused by valve guide seals wearing over time or piston ring coking, which restricts oil control. Using a high-quality synthetic oil with robust detergent and dispersant packages can help mitigate sludge formation and improve the sealing of piston rings, potentially reducing excessive oil consumption.
Another common concern for these vehicles is carbon buildup on the intake valves. Because the N55 engine utilizes direct injection for fuel delivery, fuel is injected directly into the combustion chamber rather than the intake manifold. This means fuel is not available to wash over the intake valves, leading to the accumulation of carbon deposits over time. This buildup can restrict airflow, reduce power, and cause rough idling. While fuel additives like AMSOIL P.i. Performance Improver Gasoline Additive can help clean injectors and combustion chambers, the nature of the engine design means that intake cleaning may eventually require physical maintenance. Regular use of high-solvency fuels and additives can help delay this process and maintain peak performance.
Additionally, the high temperatures generated by the turbocharger can accelerate the degradation of transmission fluid and coolant over time. The sealing materials within the cooling system and gaskets can harden or fail if the coolant loses its anti-corrosive properties. Using a premium antifreeze with a long service life can prevent corrosion and overheating, preserving the integrity of the engine block and radiator. Finally, brake fluid is hygroscopic and absorbs moisture over time, which can lower its boiling point and lead to a spongy pedal feel or reduced braking efficiency. Regular replacement with a high-performance synthetic brake fluid ensures that the braking system maintains its responsiveness and safety margins under the demands of spirited driving.
In summary, the 2018 BMW 640xi is a sophisticated machine that rewards attentive maintenance. By addressing the specific needs of its turbocharged engine, all-wheel-drive system, and high-performance components with the right synthetic lubricants, owners can ensure their vehicle remains reliable, powerful, and a pleasure to drive for many years to come.