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S55B30

3.0L Twin-Turbo M Petrol
S-series • S55 family • 2014–2020
58%
Engine Reliability
The S55 is the M division's twin-turbo inline-6 based on the N55 architecture but extensively reworked. It uses two smaller turbos for instant response and produces massive power – up to 510 hp in the CS/GTS. Crank hub and charge pipe issues are well-documented. Rod bearing concerns also apply, though less frequently than the S65.
3.0L
Displacement
I6
Layout
410–450 hp
Power
550 Nm
Torque
Petrol
Fuel
Twin-turbocharged
Aspiration
Technology & Features
Twin mono-scroll turbochargersDirect injectionForged crankshaftOil spray jet coolingClosed-deck block
Fuel SystemDirect injection
ValvetrainDOHC 24-valve, Double-VANOS
4
Known Issues
1
Critical
3
Wear Items
3
Applications

Known Issues – S55B30

critical Crank Hub Slip Moderate (~20%)
The press-fit crank hub can slip under high load, losing timing synchronization and causing catastrophic engine damage. More common on tuned cars but can affect stock. Aftermarket pinned solutions are strongly recommended for tracked or tuned cars.
Typical Mileage
Mileage independent – load dependent
Est. Repair Cost
€500–€1,000 (proactive pin) or €10,000+ (engine damage)
DIY Friendly
✗ Specialist
Sudden loss of powerEngine misfiresCatastrophic timing loss
medium Charge Pipe Failure Very Common (>40%)
Factory plastic charge pipe cracks or blows off under boost. Aftermarket aluminium replacement is essentially required.
Typical Mileage
20,000–60,000 km
Est. Repair Cost
€100–€300 (aftermarket)
DIY Friendly
✓ Yes
Sudden boost lossLimp modeWhistling noise
high Rod Bearing Wear Moderate (~20%)
Rod bearings can wear prematurely, especially on cars driven hard or with infrequent oil changes. Less critical than S65 but still worth monitoring via oil analysis.
Typical Mileage
80,000–150,000 km
Est. Repair Cost
€2,000–€4,000
DIY Friendly
✗ Specialist
Knocking noiseMetal in oil
medium Oil Pan / Valve Cover Leaks Common (~30%)
Oil leaks from valve cover gasket and oil pan gasket are common at higher mileages.
Typical Mileage
60,000–120,000 km
Est. Repair Cost
€400–€1,000
DIY Friendly
✓ Yes
Oil smellOil dripsSmoke from engine bay

Wear & Maintenance – S55B30

Spark Plugs Every 30,000 km
NewReplace
Replacement Cost€120–€200
Wear Factor65%
Rod Bearing Inspection 80,000 km or oil analysis
NewReplace
Replacement Cost€2,000–€4,000
Wear Factor55%
Differential Fluid Every 50,000 km
NewReplace
Replacement Cost€100–€200
Wear Factor40%

Applications (3)

Transmissions (2)

6-Speed Manual (Getrag)

Getrag • 6-speed manual • 2003–2019

Getrag 6-speed manual used across a wide range of BMWs. Different models handle various torque capacities. Known for precise, mechanical shift action. The GS6-53DZ handles up to 500Nm (used with 335i/M135i).
Known Issues2
medium 2nd Gear Synchro Wear Moderate (~20%)
Second gear synchros can wear, especially on higher-torque applications, causing grinding on fast 2nd gear shifts.
Typical Mileage
100,000–180,000 km
Est. Repair Cost
€800–€1,500
DIY Friendly
✗ Specialist
Grinding into 2nd gearDifficulty downshifting to 2nd
low Clutch Release Bearing Noise Moderate (~25%)
Clutch release (throw-out) bearing develops a chirp or whine when clutch is depressed.
Typical Mileage
80,000–150,000 km
Est. Repair Cost
€400–€800 (usually replaced with clutch)
DIY Friendly
✗ Specialist
Chirping with clutch pressedWhining noiseVibration in pedal
Wear Items
Clutch Assembly 100,000–180,000 km
NewReplace
Replacement Cost€700–€1,500
Wear Factor55%
Dual Mass Flywheel 150,000–250,000 km
NewReplace
Replacement Cost€500–€1,000
Wear Factor45%
Transmission Fluid Every 80,000 km
NewReplace
Replacement Cost€50–€120
Wear Factor30%
Fluid TypeMTF-LT-4 / MTF-LT-5
Service IntervalLifetime fill (recommended every 80,000 km)

7-Speed DCT (DKG/M-DCT)

Getrag • 7-speed dct • 2008–present

BMW's dual-clutch transmission, used in performance models and the F40 1 Series. Offers lightning-fast shifts for sporty driving but can judder at low speeds. The wet-clutch design handles high torque but requires regular fluid changes. The M-DCT variant was used in M3/M4.
Known Issues2
medium Low-Speed Judder Common (~30%)
Characteristic DCT judder during low-speed maneuvers, parking, and stop-start traffic. Can sometimes be improved with a software update.
Typical Mileage
20,000–60,000 km
Est. Repair Cost
€0 (software update) – €1,500 (clutch pack)
DIY Friendly
✗ Specialist
Shuddering at low speedHesitant take-offClunking in reverse
high Clutch Pack Wear Moderate (~20%)
Clutch packs wear, especially in urban driving with frequent stop-start. More aggressive driving actually helps keep clutches clean.
Typical Mileage
80,000–150,000 km
Est. Repair Cost
€1,500–€3,000
DIY Friendly
✗ Specialist
SlippingShuddering on accelerationLoss of drive
Wear Items
DCT Fluid Change Every 60,000 km
NewReplace
Replacement Cost€200–€400
Wear Factor50%
Clutch Pack 80,000–150,000 km
NewReplace
Replacement Cost€1,500–€3,000
Wear Factor45%
Fluid TypePentosin FFL-4 / Castrol BOT 130 M
Service IntervalEvery 60,000 km