"Is the 6 Serisi 640i reliable, and what should you check?"
When buying a used BMW 6 Series 640i 2015 (F06 / F12 / F13 / LCI), the most frequently mentioned issue: oil leaks from gaskets and valve cover. Also, carbon buildup on valves and injectors, and tendency to faults are commonly reported.
Engine: N55
N55B30A · 640i · Used in this car from 2011-2018
Strengths
Engine is widely used
Good potential for chip tuning
Watch-outs
Frequent vacuum leaks
Oil and coolant leaks
Some parts are very expensive
Known engine issues
Injectors and High-Pressure Fuel PumpEarly production engines used a short-lived HPFP from the predecessor, causing many issues. A more reliable pump appeared only in March 2012. Injectors were electromagnetic from the start and have no particular problems.
TurbochargersThe BorgWarner turbo lasts long with regular quality maintenance. Main owner complaints are about rapid wastegate valve wear and actuator failure (both versions).
Timing ChainThe chain itself has decent life, stretching after 200,000 km. However, its plastic guides are very sensitive to overheating and can crack. Engines before 2012 often had bolts shearing on VANOS units.
Listed from most frequently reported, each with its source.
Oil leaks from gaskets and valve cover
Often reported
Many users report oil leaks from valve cover and oil filter housing gaskets. These leaks often appear with age or high mileage and may occasionally cause smoke, residue, and oil smell.
Engine Bay
Carbon buildup on valves and injectors, fault tendency
Often reported
Carbon buildup on intake valves is common in direct injection engines over time; this can cause sluggishness, rough idle, and reduced performance. Some injector and fuel system components are reported to be prone to failure.
Engine Internal
Charge pipes/plastic cracking or weakening
Often reported
Plastic/polycarbonate turbo charge air pipes and fittings can crack or break over time, causing pressure loss, sudden power loss, or check engine light.
Turbo
Turbo / Wastegate Issues
Often reported
Turbocharger failures are reported; abnormal noises (rattling), wastegate malfunctions, and oil contamination due to thermal stress or inadequate maintenance reducing mechanical sealing. These faults lead to performance loss.
Turbo
BMW 6 Serisi 640i technical specs
BMW 6 Serisi 640i (2015): boot 460 L; fuel use 8,2 l/100 km (urban 11,4 l/100 km · extra-urban 6,3 l/100 km); 0–100 in 5.2 s.
Boot capacity
460 L
Fuel consumption
8,2 l/100 km (urban 11,4 l/100 km · extra-urban 6,3 l/100 km)
What to look for when buying a BMW 6 Series 640i?+
When buying a 2015 640i, check service history, test drive, and look for engine/transmission warnings. Most commonly reported issues: oil leaks from gaskets and valve cover; carbon buildup on valves and injectors, fault tendency; charge pipes/plastic cracking or weakening.
What are the common problems of BMW 6 Series 640i?+
Most frequently reported issues: oil leaks from gaskets and valve cover; carbon buildup on valves and injectors, fault tendency; charge pipes/plastic cracking or weakening.
Is the BMW 6 Series 640i reliable?+
Instead of a simple yes/no, it's better to weigh proven pros and cons together. This page lists 4 verified findings.
How does Carbeak collect data?+
The cards on this page are derived from Difetti fault database records; source vehicle and target vehicle are matched by brand, fuel, engine, and generation. Topics with insufficient evidence are not shown.