2021 BMW 8 Series Problems: 6 Known Issues

On the 2019-2024 BMW 8 Series N63B44T3, the N63TU3 4.4L twin-turbo V8 in M850i models uses plastic timing chain guides that wear prematurely under the extreme heat and stress of the hot-V configuration. As the plastic guides wear, the timing chain develops slack, causing rattling on cold starts and eventually risking timing chain skip or failure. Chain skip causes piston-to-valve collision and catastrophic engine destruction ($15,000-$25,000 replacement). While the N63TU3 has improved guides over earlier N63 versions, the fundamental plastic guide material still degrades from heat cycling. Turner Motorsport offers a complete timing chain guide kit (11317594899KT) with all necessary components. Bimmerpost consensus: replace timing chain guides preventively at 80,000-100,000 miles on N63TU3 engines before catastrophic failure.

On the 2019-2025 BMW 8 Series N63B44T3, the M850i equipped with the N63B44T3 twin-turbo V8 carries forward the oil consumption tendencies of the N63 engine family, though this revision is improved over earlier versions. Oil consumption of 1 quart per 3,000-5,000 miles is still common and considered within BMW's specification. The hot-vee turbo design inherently stresses valve stem seals and turbo oil seals. High-performance driving significantly increases consumption rates.

On the 2020-2021 BMW 8 Series, bMW/NHTSA recall 21V-062 covers certain model-year 2020-2021 8 Series vehicles, including M variants, produced within the recall population window. The integrated brake system rotor and shaft may not have been welded to specification; during hard braking this can reduce braking assistance and increase stopping distance. It is a VIN-specific recall, not an all-2020-2024 module or software failure population.

On the 2019-2025 BMW 8 Series, the 8 Series equipped with Adaptive M Suspension experiences electronic damper failures, particularly in the rear. The electronically controlled dampers use solenoid valves to adjust firmness in real-time, and these solenoids can fail from fluid contamination or electrical faults. When a damper fails, the system defaults to the stiffest setting on the affected corner, creating a noticeably harsh and uneven ride. The car may also display a suspension warning and disable sport/comfort mode switching.

On the 2019-2024 BMW 8 Series, all 8 Series and M8 models experience premature tire wear, particularly on the rear tires, due to aggressive factory alignment settings. The rear suspension uses approximately -2.0 degrees of negative camber from the factory, which causes rapid inner edge tire wear. Rear tires commonly need replacement at only 9,000-15,000 miles instead of the typical 25,000-40,000 miles for performance tires. The aggressive camber is set for handling performance but is excessive for street driving and dramatically shortens tire life. Reducing rear camber to approximately -1.5 degrees through a performance alignment ($150-300) significantly extends tire life while maintaining good handling characteristics for street use. Staggered tire setup (wider rear than front) means rear tires cannot be rotated to front, compounding the wear issue. M8 Competition with its even wider rear tires is most affected.

On the 2019-2025 BMW 8 Series B58, the 840i with B58 inline-six turbo engine experiences coolant loss primarily from the plastic expansion tank cracking and the electric water pump connection failing. The expansion tank develops hairline cracks at the weld seams that are nearly invisible until significant coolant is lost. The high-performance demands of the 8 Series chassis put additional thermal stress on the cooling system compared to lighter BMW models.