Used BMW 3 Series (G20) review

Exterior:

• Many owners of both the G20 sedan and G21 wagon models have experienced issues with the sunroof rattling, squeaking, or creaking sporadically. This isn’t constant but can be annoying. Fortunately, BMW has issued a service bulletin for this, so dealerships should fix it. If you’d prefer a DIY solution, applying dry lubricant around the sunroof, particularly where it rests, should help resolve the issue.
• Some early 4 Series convertible models, while not directly related to the 3 Series, have had roof mechanism failures, which can be extremely costly to repair. It’s a cautionary note for BMW owners who are interested in vehicles with complex roof systems.
• Owners of the 3 Series have also reported problems with the power-folding mirrors. Sometimes, both mirrors will open, but only one will fold back, or only one will open while the other remains folded. The auto-dip function, which is meant to engage when reverse parking, can also malfunction, either failing to dip or failing to return to the normal position.
• These mirror issues are often caused by moisture seeping into the mirror housing, although sometimes the problem stems from the mirror control panel inside the door. Some owners have faced resistance from dealerships when seeking warranty repairs for the control panel, only getting it fixed after heated discussions.
• Another reported exterior issue is with the active grille. Sometimes, one side of the grille will remain closed while the other opens, or the grille may fail to open altogether, especially in hot climates. This can result from faulty actuators or software problems.
• Fortunately, these exterior issues are more common on pre-LCI (Life Cycle Impulse) models. After the LCI update and particularly since the LCI 2 update, complaints have been significantly reduced, and most issues are covered under warranty.

Interior:

• Many G20 and G21 owners have expressed frustration with BMW’s over-the-air software updates. These updates are meant to be done remotely but are often hit-or-miss. Owners have reported that updates sometimes seem successful, only for features like blind-spot alerts to work intermittently. Others experience persistent update notifications that never actually initiate.
• The wireless phone charger is another problematic feature for some owners. In extreme cases, the charger has overheated phones to the point of triggering temperature warnings. This can be concerning for those who rely on wireless charging in their vehicles.
• While not as common, there have been reports of wireless Apple CarPlay and Android Auto dropping connections sporadically. Bluetooth connectivity has also been an issue in earlier models. For Android Auto, ensure that the car’s software has been updated, as some models may require an update for proper functionality.
• Some owners who still listen to the radio have complained that the car automatically reorganizes saved radio stations in numerical order, even if you’ve saved them in a different order. Although this seems like a small annoyance, it’s reflective of software quirks that frustrate some owners.
• The base sound system can also have issues, particularly with the centre speaker cover rattling. Fortunately, this is an easy fix—adding some felt tape to the clips of the speaker cover can eliminate the rattle, and there are guides available in owners’ forums.

Mechanical:

• BMW’s G20/G21 engines use a modular design, meaning that the 3-, 4-, and 6-cylinder engines share many components, such as pistons, connecting rods, and timing chains. While this is efficient for production, it also means that common problems, such as oil leaks and timing chain issues, affect multiple engine types.
• Common mechanical issues include oil leaks from the oil filter housing and oil cooler, as well as coolant leaks from the water pump, thermostat, or radiator. These leaks are typical wear-and-tear problems but can become expensive if not addressed promptly.
• Carbon build-up on the intake valves is a known issue with direct-injection engines, which affects performance over time. Another major issue is timing chain wear or failure, which is particularly problematic because the timing chain is located at the back of the engine, making repairs difficult and costly.
• Turbo or wastegate actuator problems can also arise, along with Valvetronic actuator oil leaks, which can lead to electrical issues if oil seeps into the wiring harness. High oil consumption is another common complaint.
• Engine mounts on the G20/G21 are often a weak point, with many owners reporting that they need replacement before the 100,000 km mark. This is a particular concern for those looking for long-term reliability.
• For those considering the M340i, be wary of modified examples. While these engines are capable of producing high horsepower, tuning them for more power can affect long-term reliability, contrary to what some tuners might claim. If you do plan to modify, only use high-quality components and work with reputable specialists.
• Diesel engines in the G20/G21 range can also suffer from timing chain problems. Additionally, EGR (exhaust gas recirculation) cooler leaks are common, leading to coolant loss. Diesel Particulate Filters (DPFs) can become clogged, often due to underlying issues such as boost leaks or a clogged MAP sensor, both of which are frequent issues in these engines.
• A key concern with both petrol and diesel engines, as well as hybrids, is BMW’s condition-based servicing and extended service intervals. These long intervals between services contribute to premature wear and can negatively affect the reliability of the engines.
• To mitigate mechanical issues, it is recommended that you change the oil every 10,000 km (or 6,000 miles) rather than relying on the manufacturer’s longer intervals. Extended service intervals and long-life oils may lead to accelerated engine wear, reducing the lifespan of otherwise well-engineered engines.

Finally, always ensure that you get a pre-purchase inspection and a vehicle history check when considering a used G20 or G21. This can help identify any potential mechanical or electronic issues before they become costly repairs.