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BMW N46
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BMW N46
Verdict
RISKY · 48/100
Est. cost /3yr
€1,500-4,500 over 3 years depending on timing chain and valve seal status at purchase
Oil interval
10,000 km
Recalls
1
Worst issue
Timing Chain Stretch & Guide Failure
CRITICAL
BMW N46
E90/E92 · Pre-LCI
Timing Chain Stretch & Guide Failure
€1,500-3,500
CRITICAL
Valve Stem Seal & Oil Consumption
€800-2,500
HIGH
Valve Cover Gasket Oil Leak
€150-400
MODERATE
Low Oil Pressure / Oil Pressure Sensor Faults
€100-600
MODERATE
Lambda / O2 Sensor Faults
€80-300
LOW
Engine Crankcase Overpressure
€50-250
LOW
BMW N46
E90/E92 · Pre-LCI
•Cold-start the engine and listen carefully for any chain rattle or knocking in the first 10-30 seconds, walk away if heard
•Request full service history showing oil changes no longer than every 10,000 km; reject any car with 30,000 km intervals
•Perform or request an OBD scan using INPA or ISTA for live lambda data, timing faults, and valvetronic fault codes
•Inspect the top of the engine and valve cover area visually for oil seepage or burnt oil residue indicating gasket leaks
•Check the oil cap for excessive crankcase pressure (strong blow when removed) and inspect the dipstick for milky oil indicating head gasket issues
•Verify the Takata airbag recall status via VIN before purchase
•Confirm whether the specific car has the earlier 150hp (pre-September 2007) or later 170hp (post-September 2007) N46N tune, this affects performance expectations and, in some markets, insurance/tax bands, but not the underlying timing chain risk
BMW N46
E90/E92 · Pre-LCI
Timing chain, upper guide rail, and tensioner
Inspect at purchase; replace proactively if no service history or if rattle present on cold start
100,000 km
Valve stem seals
Monitor for blue smoke on cold start; plan replacement if oil consumption is elevated; be aware piston rings can also be a contributing factor
120,000 km
Valve cover gasket
Inspect at every service; replace on any sign of seepage to prevent oil-on-hot-metal risk
80,000 km
PCV / crankcase breather system
Inspect and clean or replace to prevent overpressure and seal failures
100,000 km
BMW N46
E90/E92 · Pre-LCI
Air Bags, Frontal Passenger Side Inflator Module
Takata airbag inflator may rupture and deploy with excessive force, posing injury or fatality risk to occupants
BMW N46
E90/E92 · Pre-LCI
✓Smooth, free-revving naturally aspirated character with no turbo complexity
✓No turbo-related failure modes, simpler drivetrain than later N20 variants
✓Well-documented issues mean repair procedures are established and parts are widely available
✓Valvetronic variable valve lift system provides reasonable efficiency for a NA engine
✓Extensive community knowledge base on E90 forums for DIY repairs
BMW N46
E90/E92 · Pre-LCI
Real consumption
8.8 L/100km
Official consumption
6.6 L/100km
Oil interval
10,000 km
Oil spec
BMW Longlife-01 5W-30 fully synthetic (e.g. Castrol Edge 5W-30 LL or Shell Helix Ultra 5W-30)
Est. cost /3yr
€1,500-4,500 over 3 years depending on timing chain and valve seal status at purchase
BMW N46
E90/E92 · Pre-LCI
150 hp · 200 Nm
2005-2007
170 hp · 210 Nm
2007-2013
Do not choose between the 150hp and 170hp N46 tunes based on chain reliability, since both share the same timing chain, guide, and tensioner design and neither has a documented fix that reduces chain risk. The 170hp post-2007 tune is a genuine power increase for European cars, worth confirming for performance and tax-band reasons, but treat every N46 the same way at purchase: demand documented short-interval oil changes, a clean cold-start with no chain rattle, and proof of chain replacement if the car is over 100,000 km with no history. Age and service history matter far more here than which power figure is stamped on the V5.