Fragile cooling system components
Often reportedPlastic pipes, fittings, and connectors in the cooling circuit of B48 engines can become brittle over time, leading to cracks, coolant leaks, and potential overheating.
Cooling
When buying a used BMW 5 Series 520i 2021 (G30/G31/F90 LCI), the most commonly reported issue is fragile cooling system components. Carbon buildup (direct injection) is also frequently mentioned.
Engine varies by trim; verify the engine code on the listing.
Listed from most frequently reported, each with its source.
Plastic pipes, fittings, and connectors in the cooling circuit of B48 engines can become brittle over time, leading to cracks, coolant leaks, and potential overheating.
Cooling
Carbon deposits can accumulate on intake valves over time in the 2.0 direct injection engine, potentially causing poor throttle response, rough idle, and reduced efficiency.
Engine Internal
Reported issues with valve control systems (VANOS/Valvetronic) can cause uneven power delivery, check engine light, or loss of performance at low RPM.
Engine Internal
Some B48 engine versions report timing system issues (chain, guides, or tensioner) causing metallic noises when cold or at low RPM, check engine light, or timing irregularities.
Timing chain
Same trim, different year
We only publish claims we can verify. Cards come from Difetti fault records matched to this vehicle on brand, fuel, engine and generation.