"Is the 3 Serisi 325li reliable, and what should you check?"
When buying a used BMW 3 Series 325li 2021 (G20 / G21 / G80), the most commonly reported issues are: faulty plastic oil filter housing and worn engine mounts. Also, cooling system: expansion tank and pumps are frequently reported.
Engine: B48
B48B20 · 325li · Used in this car from 2019-2021
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.
Faulty plastic oil filter housing and worn engine mounts
Often reported
The plastic oil filter housing is a weak point; cracks, breakage, or leaks at the connection points are reported. Some recommend replacing it with an updated aluminum version. Additionally, some G20 owners report premature wear of engine mounts, causing vibrations during deceleration/acceleration and a 'thump' sensation during torque transfer.
Engine Bay
Cooling system: expansion tank and pumps
Often reported
Italian forums report cooling system anomalies including leaks from the radiator expansion tank, faulty cap/expansion tank, water pumps, and thermal components, requiring repair.
Cooling
Oil leaks from valve cover gaskets and seals
Often reported
Frequent oil leaks reported from the valve cover, gaskets, and filter ring seals.
Engine Bay
BMW 3 Serisi 325li technical specs
BMW 3 Serisi 325li (2021): fuel use 6,8 l/100 km; 0–100 in 8.2 s.
What should I look for when buying a BMW 3 Series 325li?+
When buying a 2021 model 325li, check the service history, test drive, and look for engine/transmission warnings. The most commonly reported issues are: faulty plastic oil filter housing and worn engine mounts; cooling system: expansion tank and pumps; oil leaks from valve cover gaskets and seals.
What are the common problems of the BMW 3 Series 325li?+
The most commonly reported issues are: faulty plastic oil filter housing and worn engine mounts; cooling system: expansion tank and pumps; oil leaks from valve cover gaskets and seals.
Is the BMW 3 Series 325li reliable?+
Rather than a simple yes/no, it's best to consider the proven pros and cons together. This page lists 3 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.