BMW 4.8i
Bavaria's first V8 with fully variable valve train: Valvetronic handles load control almost without the throttle butterfly, giving the N62B48 an unusually smooth throttle response. Cold, it unmistakably sounds like a V8 — deep, cultured rumble at idle; at 4,000 rpm the note shifts to a silky high-frequency range. Aluminium block with magnesium bedplate, light and torsionally stiff. The construction is complex: valve stem seals harden from 130,000 km; blue smoke after standing is the first sign. The coolant transfer pipe between the cylinder heads — an aluminium pipe with O-ring deep in the V — develops leaks without anything visible from outside. Budget generously for maintenance.
SUV with a Proper V8 Heart
In the E70 the N62B48 powers a genuine all-rounder. Ample shove, the driving experience is more GT than sport — but the V8 at full chat makes up for a lot. Effortless on the motorway, relaxed rather than agile on twisty roads. Service items identical to every N62.
Engine Weaknesses 9
Rubber seals harden from ~130,000 km; oil passes the valve stems into the combustion chamber. Classic finding: blue smoke on cold start after standing. Special tool allows replacement without removing the camshafts.
Symptoms: Blue-white smoke from the exhaust on cold start and after idle periods. Increased oil consumption (0.5–1 L/1,000 km). No smoke when warm under load.
Aluminium pipe between the cylinder heads in the V seals with O-rings. These harden over time and coolant disappears without visible external leakage. Repair requires removal of the intake manifold.
Symptoms: Gradual coolant level drop without visible leakage. Sweet smell in the engine bay. Coolant warning light. In advanced stages risk of overheating.
The original plastic impeller can break at high mileage and spin freely — engine overheats without warning. Preventive replacement at 150,000 km with a metal impeller is recommended.
Symptoms: Engine temperature rises sharply and suddenly. Slight ticking at idle that disappears when driving. Coolant warning light. In extreme cases overheating damage.
Intermediate levers wear into the eccentric shaft bearing surfaces, mostly due to condensate in the oil from short-trip driving. Valvetronic enters limp mode; misfires on individual cylinders.
Symptoms: Misfires on cold start. Engine light. Power loss. Valvetronic limp mode with restricted drivability. Misfires are cylinder-specific.
The N62 has two electrically controlled thermostats. Failures cause the engine to run permanently cold or to overheat. Rarely a sudden failure — usually gradual.
Symptoms: Engine does not reach operating temperature or runs too hot. Heating works poorly. Increased fuel consumption. Coolant temperature fault code.
With long oil change intervals or short-trip driving, sludge builds up in the VANOS solenoid valves — camshaft adjustment responds sluggishly or not at all.
Symptoms: Rough cold start. Lack of power in the lower rev range. Engine light with camshaft fault code. Ticking noise on startup.
Rubber seal on the alternator bracket ages and leaks. Oil collects on the driver's side. Removal requires engine lifting — high labour cost for an inexpensive part.
Symptoms: Oil seeping from driver's side of engine bay. Oil spots under the car. Occasional oil smell. Oil can drip onto hot engine parts and smoke.
CCV membrane tears at high mileage; excessive crankcase vacuum pushes oil into the intake tract. Increased oil consumption also under load.
Symptoms: Strong vacuum when opening the oil filler cap. Oil in the intake tract. Increased oil consumption. Blue smoke even under load.
Check valve of the secondary air pump gives way, exhaust flows back and damages the pump. Engine light during cold start phase, no drivability fault.
Symptoms: Engine light after cold start. Noise from engine bay on cold start. No noticeable power loss. Fault often clears itself after warm-up.
Vehicle Weaknesses 8
Air suspension compressor and air springs fail frequently from 80,000 km. Average lifespan of air springs is 100,000–120,000 km. Aftermarket springs (Arnott/Continental) cost around €115 each — BMW pricing is significantly higher.
On cars with a panoramic roof, blocked drainage channels can allow water into the boot, where sensitive control units sit beneath the load floor trim. Consequential costs are considerable.
The xDrive transfer case ATC700 wears prematurely with mismatched tyre rolling circumferences or neglected oil changes. Juddering on pull-away is the typical early symptom. Replacement can cost up to €5,000.
From around 150,000 km the rear air springs become porous; the compressor runs continuously and overheats. Both sides should be replaced simultaneously as the second bellows typically follows shortly after.
Electronically controlled Adaptive Drive dampers fail from 120,000 km; replacement is only possible with BMW parts and costs around €800 per damper. Standard suspension is far more trouble-free.
A creaking, sometimes leaking panoramic roof is a well-known TÜV defect on the E70. Recommendation: choose a car without a panoramic roof. A new roof centre unit costs around €330 without fitting.
iDrive system shows frequent faults after 100,000 km. The ignition switch can prevent the car from starting. The electric water pump on the N55 is prone to wear.
Up to model year 2010, BMW used cheaper sealing compound rather than proper gaskets for the tail lights, causing moisture ingress and short circuits in the rear lights.
Reports & Tests
1369 owner complaints filed with NHTSA (2006–2013). Most reported: Airbags (427), Engine (312), Electrical (183).