"Is the 5 Serisi 520i reliable, and what should you check?"
When buying a used BMW 5 Series 520i 2018 (G30 / G31 / F90), the most frequently mentioned issue is cooling system problems. Oil leaks and consumption are also commonly reported.
Engine: B48
B48B20B · 520i · Used in this car from 2018-2019
Known engine issues
Cooling systemEarly versions of this engine were equipped with short-lived cooling system pipes that often burst, but later plastic was replaced with rubber and the problem went away. Also on the forum they often complain about the short-lived water pump, radiators and coolant expansion tank cap.
Oil consumptionCompared to its predecessors, B48 units are not as prone to oil consumption, but closer to 100,000 km the valve stem seals usually harden and consumption appears. Also worth noting are regular leaks from the oil filter housing, it needs to be monitored.
Floating idleFloating idle speed or regular appearance of lean mixture errors indicate failure of the fuel tank ventilation valve. But it is inexpensive.
+2 more issues on the engine detail page
Known issues and risks
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 critically low 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, there is a risk of chain stretch and timing slip.
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 (2018): boot 570 L; fuel use 6,2 l/100 km (urban 7,5 l/100 km · extra-urban 5,5 l/100 km); 0–100 in 8.2 s.
Boot capacity
570 L
Fuel consumption
6,2 l/100 km (urban 7,5 l/100 km · extra-urban 5,5 l/100 km)
What should I look for when buying a BMW 5 Series 520i?+
When buying a 2018 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/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.