BMW 735i
3.6 litres and 272 hp — the entry point into the N62 world. Constructionally identical to the other N62 variants: aluminium, magnesium bedplate, Valvetronic, double VANOS. The lower thermal load has one advantage: the big problems — valve stem seals, coolant transfer pipe, Valvetronic wear — tend to appear somewhat later than on the more heavily stressed variants. At idle barely distinguishable from a six-cylinder; at revs the V8 character becomes apparent. Short oil change intervals are also mandatory here.
V8 Entry-Level, 7 Series Comfort
The N62B36 in the E65 is an unhurried engine: no excessive power demands, no thermal stress — but a V8 note that makes the saloon something special. The big N62 issues tend to surface later here, because the motor is rarely pushed hard.
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 10
The electronic steering column lock can seize and prevent the car from starting. BMW charged around 1,800 € for repair. One of the most expensive electrical problems of this generation.
The E65 is considered an electrical nightmare: comfort access, ISOFIX, various control units, and body electronics can fail. Even minor repairs easily cost over 1,000 €.
The rear air suspension on the E65 is a frequent and expensive weak point. Air bellows and compressor typically fail from 100,000 km. The car sags at the rear, especially after standing.
Blocked panoramic roof drains let water through the C-pillar into the boot. Up to 7 control units are located there.
Hydraulic power steering pump fails. Faulty vane pump or leaking pressure hoses as causes.
A weak battery causes apparent multiple faults: Dynamic Drive, DSC, gearbox, and steering show simultaneous errors.
Plastic water pipe on top of the N62 V8 engine becomes porous and leaks. Coolant loss can lead to overheating.
Solenoid valves in the air suspension compressor scale up from condensation. Compressor can often be repaired cost-effectively.
The E65 comfort access fails frequently — from flat key batteries to faulty door handles and the CAS control unit. Diagnosis is complex and repairs accordingly expensive.
The E65's four-zone climate control frequently develops temperature regulation faults in individual zones. The water valve and IHKA climate control units are wear items that regularly fail after 10+ years.
Reports & Tests
15 owner complaints filed with NHTSA (2001–2008). Most reported: Electrical (3), Airbags (3), Suspension (3).