"Is the 5 Serisi 520i reliable, and what should you check?"
When buying a used BMW 5 Series 520i 2017 (G30 / G31 / F90), the most frequently mentioned issue is cooling system problems. Additionally, oil leaks and consumption are also commonly reported.
Engine: N20
N20B20B · 520i · Used in this car from 2011-2017
Strengths
Relatively low fuel consumption
Good potential for chip tuning
Watch-outs
Timing chain has low service life
Frequent leaks from under valve cover
Plastic pipes have short lifespan
Known engine issues
Timing chainThe most famous weak point of this engine is the modest service life of the timing chain, sometimes it lasts less than 80,000 km. Note that units after 2015 have a longer service life.
Oil pump chainAnother widespread problem of early engines was the breakage of the oil pump chain with fatal consequences. A new thicker chain appeared in September 2012.
Piston destructionN20B20A engines with compression ratio 10.0 are easily tuned and run without much trouble, but N20B20B engines with compression ratio 11.0 suffer from detonation after chip tuning.
Listed from most frequently reported, each with its source.
Cooling system problems
Often reported
Frequent leaks or failures are reported in cooling system components such as water pump, thermostat, or expansion tank.
Cooling
Oil leaks and consumption
Often reported
Oil leaks from gaskets are commonly reported on B48 engines, requiring frequent oil top-ups. The most cited areas are the oil filter housing, valve cover gasket, and oil pan; if unresolved, it can lead to critical oil levels and engine damage.
Engine Internal
Timing belt/chain tensioner
Often reported
In some B48 engine examples, startup noises or rattling from the timing system may be heard, indicating wear or failure of the belt/chain tensioner. If neglected, chain stretch and timing slip can occur.
Timing chain
Injector and high-pressure fuel system issues
Often reported
Injector failure or clogging, and less commonly high-pressure pump issues, are reported; this can cause hard starting, rough idle, power loss, and increased fuel consumption.
Fuel System
Turbo/wastegate failures or noise
Often reported
Some B48 units report turbocharger anomalies: wastegate rattle, loss of boost pressure, or premature wear. Typical symptoms include power loss, noise at idle or acceleration, and in severe cases, turbo replacement may be required.
Turbo
BMW 5 Serisi 520i technical specs
BMW 5 Serisi 520i (2017): boot 560 L; fuel use 7,2 l/100 km (urban 9,5 l/100 km · extra-urban 5,8 l/100 km); 0–100 in 8.3 s.
Boot capacity
560 L
Fuel consumption
7,2 l/100 km (urban 9,5 l/100 km · extra-urban 5,8 l/100 km)
What should I look for when buying a BMW 5 Series 520i?+
When buying a 2017 520i, check the service history, perform a test drive, and look for engine/transmission warnings. The most commonly reported issues are: cooling system problems; oil leaks and consumption; timing belt/chain tensioner.
What are the chronic problems of the BMW 5 Series 520i?+
The most commonly reported issues are: cooling system problems; oil leaks and consumption; timing belt/chain tensioner.
Is the BMW 5 Series 520i reliable?+
Instead of a simple yes or no, it's necessary to evaluate the proven pros and cons together. This page lists 5 verified findings.
How does Carbeak collect data?+
The cards on this page are derived from Difetti fault database records; the source vehicle and target vehicle are verified for brand, fuel, engine, and generation compatibility. Topics with insufficient evidence are not shown.