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3 Series G20 / G21
G20 • 2019–2025 • Sedan, Touring
3
Engine Options
6
Known Issues
0
Critical Issues
78%
Reliability Score
Facelift (LCI) – 2022
- Curved display with iDrive 8
- Updated kidney grille design
- New mild-hybrid 48V systems
- Revised front and rear styling
78% – Good
Engines
B48B20 – 2.0L Turbo Petrol
320i, 330i • 184–258 hp • 300–400 Nm
Displacement 2.0L
Layout I4
Fuel Petrol
Transmission 8-Speed Automatic (ZF 8HP)
Known Issues1 issue
medium
Coolant System Weakness Occasional (~15%)
Electric water pump or thermostat may fail prematurely, particularly on early production units.
Typical Mileage
60,000–100,000 km
Est. Repair Cost
€400–€800
DIY Friendly
✗ Specialist
Overheating warningCoolant lossReduced power
B58B30 – 3.0L Turbo Petrol
M340i • 374 hp • 500 Nm
Displacement 3.0L
Layout I6
Fuel Petrol
Transmission 8-Speed Automatic (ZF 8HP)
Known Issues1 issue
medium
Valve Cover Leak (Early Production) Occasional (~15%)
Early B58 engines can develop a valve cover gasket leak. Generally well-sorted on later production.
Typical Mileage
60,000–100,000 km
Est. Repair Cost
€300–€500
DIY Friendly
✓ Yes
Oil smellSeepage around valve cover
B47D20 – 2.0L Diesel
318d, 320d • 150–190 hp • 350–400 Nm
Displacement 2.0L
Layout I4
Fuel Diesel
Transmission 8-Speed Automatic (ZF 8HP)
Known Issues3 issues
high
EGR Cooler Leak Moderate (~20%)
EGR cooler can develop internal leaks, mixing coolant into the exhaust system.
Typical Mileage
80,000–150,000 km
Est. Repair Cost
€500–€1,000
DIY Friendly
✗ Specialist
Coolant lossWhite exhaust smokeOverheating
medium
Injector Seal Leak Moderate (~25%)
Copper injector seals deteriorate, causing a black tar-like residue around injectors and diesel smell.
Typical Mileage
80,000–130,000 km
Est. Repair Cost
€200–€400
DIY Friendly
✓ Yes
Diesel smellBlack residue around injectorsRough idle
medium
EGR Valve Clogging Common (~30%)
EGR valve clogs with carbon, especially on cars doing mostly short trips.
Typical Mileage
80,000–130,000 km
Est. Repair Cost
€300–€600
DIY Friendly
✓ Yes
Reduced powerRough idleEML light
Common Issues (G20-specific)
Electrical 1
low
iDrive Software Glitches Common (~25%)
Random iDrive reboots and software glitches. Usually resolved with software updates.
Typical Mileage
N/A – software
Est. Repair Cost
€0 (software update)
Category
Electrical
Screen freezeRandom restartBluetooth disconnects
Wear Items
B48B20 – Wear Items
320i, 330i
Spark Plugs
Every 60,000 km
Replacement Cost€80–€150
Wear Factor50%
Brake Pads (Front)
30,000–50,000 km
Replacement Cost€150–€400
Wear Factor55%
B58B30 – Wear Items
M340i
Spark Plugs
Every 60,000 km
Replacement Cost€120–€200
Wear Factor50%
B47D20 – Wear Items
318d, 320d
DPF (Diesel Particulate Filter)
150,000–250,000 km
Replacement Cost€800–€2,000
Wear Factor40%
Glow Plugs
80,000–120,000 km
Replacement Cost€100–€250
Wear Factor45%
All Variants
All Variants
Complete list of model variants for G20 / G21