BMW M8 G15

The most mature S63 generation: revised bearing geometry, Valvetronic, 600–635 hp depending on variant. The sound remains S63-typical — no raw AMG aggression, rather a deep V8 growl with turbo whistle as an accent. Sonically restrained from the factory, which many F90 owners correct with aftermarket exhaust systems. The M xDrive system can be switched to pure rear-wheel drive — in dry 2WD mode the F90 becomes a 625 hp drift tool. Electric wastegate actuators are the new weakness of this generation. Oil changes every 8,000 km with quality full synthetic; do not rely on Longlife intervals. The con rod bearing issue is reduced but not eliminated by the revised geometry — oil analysis remains worthwhile.

• !! Connecting rod bearing wear (mitigated) from 100,000 km

  Revised connecting rod design compared to S63TU with 8 additional oil drillings. Despite this, documented failures exist: a workshop case study shows an F90 M5 with connecting rod and crankshaft damage. The F90 sees the problem less often than the F10.

  Symptoms: Noticeable knocking from the engine, metal particles in the sump and filter housing, crankshaft damage as a consequence of delayed diagnosis
  2,000–4,000 $
  Ad connecting rod bearing S63B44T4Lagerschalen BMW M5 F90Rod Bearing S63T4 F90
• !! High-pressure fuel pump (HPFP) failure from 120,000 km

  The high-pressure fuel pump can fail at high mileages or with aggressive use. Fuel pressure drop causes noticeable power loss and can secondarily damage injectors and turbochargers.

  Symptoms: Power loss under high load, hard starting, fault code fuel pressure too low (P0087), stumbling at full throttle.
  1,200–3,000 $
  Ad high-pressure fuel pump S63T4HPFP BMW M5 F9013518604229
• !! Turbo coolant lines V-valley heat damage from 80,000 km

  The turbochargers mounted in the V-valley are subjected to extreme radiant heat. Coolant lines and connections can crack through thermal cycling. Allow an adequate cool-down phase after full-load driving.

  Symptoms: Coolant loss in the turbo area, coolant smell after driving, steam from the bonnet, reduced boost pressure.
  500–1,800 $
  Ad Turbo coolant line S63T4coolantleitung Turbo BMW M5 F90

+ 6 more engine weaknesses + vehicle weaknesses

Third-generation hot-V eight-cylinder — turbos sit INSIDE the cylinder V, not on the sides. This shortens exhaust paths and improves response but creates extreme temperatures in the engine valley. Electric wastegates react in milliseconds, 350 bar injection and forged internals. In Sport+ with the exhaust flap open, a deep bass-heavy V8 growl with turbo whoosh and pops on throttle lift — less theatrical than AMG but more refined. Noticeably sharper than TU/TU2, and the notorious original N63 with its oil issues is light years away. Stage 1 software tune realistically yields 570+ HP on stock turbos. Most reliable N63 variant, but the hot-V architecture demands discipline: short oil change intervals (max 5,000 miles) with 0W-40 are mandatory, always let the engine idle after hard driving. Check starter motor recall (overheating/fire risk) at the dealer.

• !! Recall: Starter Motor — Overheating with Fire Risk

  Repeated start attempts can cause the starter motor to overheat from electrical overload and ignite combustible materials in the engine compartment. Affects over 340,000 BMW vehicles (2019–2021). Free repair at BMW dealer.

  0–0 $
• !! Valve stem seals — residual risk at high mileage from 160,000 km

  The fundamental design with valve stem seals is retained. At very high mileages (>150,000 km) and aggressive use the seals can suffer thermal wear. Repair costs €3,300–3,800 (approx. 6–8 hours' work, engine removal required).

  Symptoms: Increased oil consumption at very high mileages, slight blue smoke on cold start or after extended standstill, oil deposits in the exhaust
  3,290–3,800 $
  Ad valve stem seal N63TU3valve stem seal N63B44TU3 set
• !! Timing chain guides at risk from oil quality degradation from 150,000 km

  The plastic timing chain guide rails are sensitive to degraded engine oil. Extended oil change intervals (BMW Longlife) accelerate degradation. Complete engine removal (~40 labour hours) required; preventive replacement at >150,000 km is advisable.

  Symptoms: Rattling on cold start, engine warning light, occasionally loud clattering with heavily degraded oil
  4,500–8,000 $
  Ad timing chain N63TU3 settiming chainnführung N63B44TU3chain tensioner N63TU3

+ 6 more engine weaknesses + vehicle weaknesses