BMW 545e
Closed-deck aluminium block as standard — a feature normally reserved for racing engines. Water-cooled turbo with mechanical wastegate linkage that rattles at cold start — by design, not dangerous. Barely audible at idle; from 3,000 rpm a rich, deep six-cylinder thrust builds linearly to 6,500. The B58 sounds fuller than the S55 from outside — but inside the motorsport aggression is absent. Dual injection (direct + port) reduces intake valve carbon build-up significantly. The PCV membrane in the valve cover is the known weakness: BMW had to extend the warranty to 15 years. Plastic oil filter housing cracks around 100,000 km — coolant mixes into oil, act immediately. Oil changes every 10,000 km; inspect the cooling system from 70,000 km. Tuning: Stage 2 brings 500 hp — the closed deck makes it possible.
540i benchmark
340 hp inline-six, ZF-8HP near-perfect — agile despite the luxury brief.
Engine Weaknesses 12
On B58-equipped M140i/M240i the oil filter can disintegrate on first change and distribute filter material through the oil circuit. BMW covers the costs with proven service history.
Symptoms: Oil pressure warning, metallic noises, engine damage after oil change
The plastic oil filter housing becomes brittle from heat cycling and cracks — often during oil changes from overtightening the filter cap. Coolant and oil mix; engine damage likely if unnoticed.
Symptoms: Milky oil on the filler cap, coolant loss without visible leak, oil pressure warning, coolant level drops slowly
The PCV membrane in the integrated valve cover tears or hardens from heat cycles. Crankcase builds positive pressure, oil is forced through seals. BMW extended the warranty to 15 years/150,000 miles.
Symptoms: Whistling or squealing from the engine bay, white or blue smoke, rough idle, oil in the charge pipe or air filter
Many B58 owners observe a regularly dropping coolant level without external leaks. Suspected components are heat exchanger gaskets, plastic lines, and the expansion tank cap.
Symptoms: Coolant warning message; coolant level regularly low after topping up; no visible leak on the ground
The mechanical seal of the belt-driven water pump fails prematurely. Coolant seeps from the weep hole below the pulley. Often only slowly detectable — early visual inspection is advisable.
Symptoms: Coolant residue or drops under the engine, coolant level drops without major visible leak, coolant level warning
The small plastic bleed hose between the oil filter housing and expansion tank becomes brittle and develops hairline cracks. Often perceived as coolant loss with no obvious cause.
Symptoms: Coolant loss without visible puddle, damp spot at oil filter housing, pressure loss in cooling system
The standard plastic charge pipe between the intercooler and throttle body bursts under boost pressure — especially on tuned cars or in summer. Immediate limp mode.
Symptoms: Immediate power loss, limp mode, audible hissing or bang when it splits, engine runs with severely reduced power
Like the B48, the B58 turbocharger wastegate linkage rattles by design on cold start and at low revs. BMW has issued a specific repair kit as a goodwill measure.
Symptoms: Metallic clattering or rattling from the turbo area on cold start; sounds like a loose metal bolt; usually only in the first few minutes
VANOS solenoid valves on the B58 get clogged by oil-contaminated deposits or fail electrically. Individual valves are cheap to replace; delay risks follow-on damage to the camshaft phasers.
Symptoms: Idle fluctuation; power loss below 3,000 rpm; ticking on cold start similar to a diesel; fault code 2A82 or 2A87
Direct injection does not wet the intake valves — blowby vapours bake carbon onto them. The B58 also has port injection which slows carbon build-up significantly compared to pure DI engines.
Symptoms: Rough cold start, power loss at higher revs, misfires, increased fuel consumption
The auxiliary belt tensioner rattles on cold start — sometimes from just a few thousand kilometres. BMW warranty repair, but problem can return after replacement.
Symptoms: Metallic rattling or clattering on cold start, noise fades after warm-up, worsens when AC is switched on
The rubber valve cover gasket hardens from extreme heat cycling and leaks oil onto spark plugs and the engine block. Separate from the PCV issue — pure seal degradation without membrane failure.
Symptoms: Burning oil smell, oil marks on engine block below valve cover, oil on spark plugs, slight oil consumption
Vehicle Weaknesses 20
BMW recalled several G60 models from 2023–2024 due to faulty cell contacts in the high-voltage battery. A defect can cause discharge and present a fire risk.
BMW recalled the 5 Series G60/G61 because a misrouted cockpit wiring harness can be damaged during pollen filter replacement. A short circuit can cause fire. KBA 16187R.
The AdBlue dosing system crystallises during long standstill or at low temperatures. Fault code 26F500 appears. NOx sensor is a classic wear point. Repair is expensive.
The flex disc (Hardy disc) in the drivetrain often cracks before 100,000 km. BMW sometimes covers it under goodwill. Replacement including prop shaft can cost 2,000 €.
A signal fault in the motor position sensor of the integrated brake system can deactivate the hydraulic brake assist. ABS and DSC fail. BMW replaces the entire IBS free of charge.
The M5 G90 weighs around 2,435 kg as a PHEV — approximately 500 kg more than the F90 predecessor. The extra weight affects dynamics and causes understeer in tight corners. The system is still very new and long-term data is lacking.
Related BMW PHEV models such as the X5 50e show CCU (Combined Charging Unit) failures below 2,000 km. Whether the M5 G90 uses identical components and is affected remains unclear — the model is too new for reliable data.
Traffic sign recognition, TPMS sensors, digital instrument cluster, and lane/parking assistance failures are frequently reported. Usually resolved by software updates.
Various suspension components (top mounts, drop links, control arms) wear out. Air suspension on the G31 Touring is a known weak point. Rear lighting fails due to wiring breaks.
The G30's iDrive system tends to crash and restart sporadically. Navigation, Bluetooth, and CarPlay are intermittently unavailable. Software updates usually only help temporarily.
Especially on M Sport vehicles, the front brakes squeal when braking lightly. BMW acknowledged the issue and released a revised brake system. No safety risk.
Some G60 drivers report occasional messages that recuperation is not working. After software updates BMW also significantly changed the hybrid drivetrain characteristics, leading to owner complaints.
The new BMW OS 9 operating system in the G60 still has various software bugs: voice control fails, assistant systems falsely deactivate, smartphone pairing is unstable.
On the G60 with M Sport suspension, noises occur at full lock or when parking. BMW dealers recommend shock absorber replacement as the fix — whether the top mount or damper is the root cause has not been conclusively determined.
A quiet rattle from the steering wheel area at 30–60 km/h on uneven road. Cause is a loose airbag pot, not the steering itself. Issue appears to be known but no official service bulletin has been issued.
Wireless CarPlay disconnects from the system sporadically; eSIM shows connection error on startup. Digital key sometimes cannot be set up. Issue occurs reproducibly for several i5 owners — often every third journey.
When steering with M Sport suspension, especially on the 520d xDrive, noises come from the steering area. Dealers in isolated cases recommended shock absorber replacement, which didn't reliably resolve the issue.
Several G60 owners report noticeable steering play and imprecise steering feel, resolved by steering rack replacement under warranty.
G60 owners report Spotify connection drops, incorrect navigation position, and driver assistance failures. Software instability with OS9 systems.
The additional weight of around 500 kg compared to the F90 M5 places considerable strain on the G90's braking system. Despite recuperative braking, mechanical brakes need replacing earlier.
Reports & Tests
16 owner complaints filed with NHTSA (2017–2023). Most reported: Seat Belts (4), Airbags (3), Body Structure (2).