Buying a used BMW 6 Series E63/E64: our reliability guide

Launched in 2003, the BMW 6 Series E63 (coupe) and E64 (convertible) embodies German grand touring. Elegant, powerful, and luxurious, it shares its technical platform with the 5 Series E60, while boasting a design by Chris Bangle that is both bold and timeless.

Combining comfort, performance, and driving pleasure, the E63 6 Series still appeals to many enthusiasts on the used car market. But like any high-end BMW from that era, it requires careful inspection before purchase.

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General reliability and design features

Produced between 2003 and 2010 , the E63/E64 6 Series is based on a structure combining aluminum at the front and steel at the rear, for a weight distribution close to 50/50. This architecture offers excellent road handling, but makes some repairs (wings or front hood) more expensive because of the aluminum parts.

All versions are equipped with a first-generation iDrive system ( CCC ), replaced by the CIC version from the facelift (2007). This update greatly improves the reliability and responsiveness of the multimedia system .
The facelift (LCI) also brings mechanical and electronic adjustments, LED lights, improved interior finish, and slightly modernized engines.

Petrol engines: from refinement to the legendary V10

The E63 6 Series was offered exclusively with petrol engines until 2007, before the arrival of the diesel version in the 635d. The six, eight, and ten-cylinder engines are generally reliable, but each has its points of concern.

630i – Inline six-cylinder (3.0L M54 then N52)

Power: 231 hp (M54), then 258 hp (N52) from 2005.
Reliability: very good, provided it is regularly maintained.
Points to watch out for:
- Frequent oil leaks (rocker cover, crankcase).
- VANOS sensors and ignition coils sometimes fail.
- On the N52, the famous “tic-tic” of the hydraulic tappets when cold may appear.
Tip: balanced and robust engine, ideal for regular use without aiming for pure performance.

645Ci – V8 4.4L (N62B44)

Power: 333 hp.
Performance: smooth, noisy, very pleasant on long journeys.
Known weaknesses:
- Oil leaks (cylinder head cover gasket, crankcase gasket).
- Wear of the valve stem seals leading to oil consumption.
- Valvetronic sensors and variable lift system can sometimes be temperamental.
Tip: Check for complete maintenance (frequent oil changes, replaced seals). A refined yet demanding piece of engineering.

650i – V8 4.8L (N62B48)

Power: 367 hp.
Advantages: a more reliable version of the 4.4L, better flexibility and slightly reduced fuel consumption.
Things to watch out for:
- Same problem with seals and oil consumption.
- Age-sensitive camshaft or crankshaft sensors.
Tip: an excellent compromise between performance and reliability, provided that minor maintenance is not neglected.

M6 – V10 5.0L (S85)

Power: 507 hp.
Reliability: exceptional engine, but very high-strung.
Critical points:
- Connecting rods and connecting rod bearings should be monitored (preventive replacement recommended after 100,000 km).
- Oil pump, VANOS regulation and sensitive engine sensors.
- The SMG III automated gearbox (hydraulic) can be expensive to repair.
Advice: reserved for enthusiasts capable of undertaking rigorous and expensive maintenance.

Diesel engines: the 635d, an interesting choice

635d – 3.0L biturbo (M57N2)

Power: 286 hp.
Strengths: generous torque, surprising fuel efficiency for a GT, very reliable if well maintained.
Known weaknesses:
- Clogged EGR valves and intake manifolds.
- Risk of breakage of swirl flaps if not removed.
- Turbocharger needs checking on high mileage vehicles.
Tip: an excellent engine for frequent driving, provided it is rigorously maintained.

How to check for known problems before buying

During the test, certain points deserve particular attention:

Timing chain : listen for any chain noise on the 6 cylinders (especially N52) and check for replacement on the N47 diesels (not present here, but sometimes confused).
Oil and leaks : inspect under the engine and around the covers for any traces of oil.
Electronics : test the iDrive, GPS, air conditioning, parking sensors, seats and adaptive headlights.
Suspension : Electronically controlled dampers (EDC) are expensive to replace, as are the front suspension arms.
Convertible roof (E64) : check the proper functioning of the mechanism and the sealing of the joints.

Equipment and electronics: beware of complexity

Highly optioned models (HUD, ventilated seats, iDrive, Night Vision…) may be attractive, but these features age more or less well.
Bugs in the iDrive CCC system were common before 2007; an update or replacement by CIC fixed many problems.

Many owners choose to install a modern CarPlay car radio ( available in our shop ) , compatible with the original system, to enjoy a current interface without losing the original aesthetics.

Verdict: Which BMW 6 Series E63/E64 should you choose?

Preferred option:

630i (after 2005) : reliable and pleasant six-cylinder engine.
650i : the best balance between luxury and performance.
635d : a solid and efficient diesel for frequent driving.

To avoid:

645Ci (pre-2005) if the maintenance is unclear or incomplete.
M6 for everyday use or without a large maintenance budget.

Pre-purchase advice

Check the complete maintenance history (oil, coolant, spark plugs, gaskets, maintenance log).
Check the automatic gearbox (no jerking when changing gears).
Examine the underside of the engine and the adaptive shock absorbers.
Test the operation of all electronic systems (air conditioning, seats, iDrive, sensors).
For the convertible, inspect the roof mechanism and the peripheral seals.

Upgrade and modernize your E63 6 Series

Even more than 15 years after its release, the BMW 6 Series E63 retains an undeniable charm.
To modernize your interior and enhance its appearance, several improvements are possible:

CarPlay/Android Auto car radio : to add GPS, Spotify and hands-free calling without modifying the original design.
Black grilles : for a sportier and more contemporary look.
New gear knob or modernized selector lever : to refresh the interior.

👉 Discover our collection of accessories and parts for BMW in our shop: CarPlay modules, aesthetic elements, replacement buttons and more.

(BUYING GUIDE) Reliability of used BMW 6 Series E63/E64 cars: our detailed review