BMW/N55
BMW · Bi-turbo

BMW 335i N55

335i·E90/E92·2010–2012·2,979 cc·Verified 13 Jul 2026

"In true BMW fashion, even the coffee mugs leak oil."

SOLID
62/ 100
"Better than N54, but still leaks"
Compare

Power Variants

306 hp · 400 Nm
N55
2009-2016
Standard tune used across 335i, 535i, X3 xDrive35i, and Z4 sDrive35i. Most common N55 configuration, single twin-scroll turbo, ECU allows for typical stage 1 tuning.
320 hp · 450 Nm
N55 (335is)
2011-2013
E92 335is runs an M Performance ECU tune with a temporary overboost function reaching 450 Nm. Fitted with reinforced forged pistons and connecting rods to handle the extra load, giving it a marginally stronger bottom end than the standard 335i despite the higher output.
326 hp · 450 Nm
N55
2013-2018
Later revision used in F10 535i, F01 740i, and M235i/M240i. Production from around 2013 onward is generally understood to use an updated rod bearing specification that reduces, but does not eliminate, the early bearing wear seen on earlier N55 units.
370 hp · 465 Nm
N55 (M2 tune)
2016-2018
BMW M2 (F87) uses a heavily reinforced N55 with forged internals, a larger turbo, and uprated cooling borrowed from M-division practice. Not directly comparable in reliability terms to lower-output variants due to the extensive internal upgrades.

Recommendation

The base 306 hp tune is the most common and cheapest to maintain, and it makes sense as the default choice for most buyers. Do not assume higher output means higher risk here: the 335is and M2 versions actually have stronger internals, forged pistons and rods, specifically because BMW allowed more torque through them. If buying a standard 335i, 535i, or X3 xDrive35i, prioritize a car with full documented oil change history and, where possible, one built after the 2013 rod bearing revision, since bearing wear remains the single biggest catastrophic risk across the whole N55 family regardless of power output.

493
Max HP
680
Torque Nm
8,000
Oil interval km
4
Recalls
8
Known issues

Known Issues

Valve Cover Gasket Oil Leak€300-700 · 60,000-120,000 kmHIGH

The valve cover gasket is a well-documented failure point on the N55. Oil leaks from the gasket can drip onto hot exhaust components and cause misfires when oil enters spark plug wells. Forum data confirms failures as early as 47,000 miles on some units.

Oil burning smell from engine bay
Misfires or rough idle
Visible oil around valve cover perimeter
Oil in spark plug wells
DIY: Moderate
Oil Filter Housing Gasket (OFHG) Leak€400-900 · 80,000-160,000 kmHIGH

The oil filter housing gasket is prone to leaking on the N55, allowing oil and coolant to mix or escape externally. This is a recurring service item across the platform, most often surfacing during a coolant top-up or oil leak inspection.

Oil or coolant leak near oil filter housing
Coolant loss without visible external leak
Oil contamination in coolant
Low oil or coolant warnings
DIY: Moderate
Rod Bearing Wear€1,500-4,000 · 100,000-180,000 kmHIGH

N55 engines can suffer spun or worn rod bearings at higher mileages, particularly on earlier production units and cars with extended oil change intervals. BMW revised the bearing specification during the production run, which appears to have reduced but not eliminated the issue on later-built engines.

Knocking or tapping from lower engine
Oil pressure warning light
Engine seizure in severe cases
DIY: Expert
Crankcase Ventilation Valve (CVV) / Oil Separator Failure€200-500 · 80,000-150,000 kmMODERATE

The CVV or oil separator can fail on the N55, leading to increased crankcase pressure, oil consumption, and external oil leaks. This is a common contributor to oil consumption complaints across the platform.

Excessive oil consumption
Blue smoke from exhaust
Oil leaks with no obvious gasket source
Rough idle
DIY: Moderate
Oil Consumption€100-300 · 60,000-150,000 kmMODERATE

The N55 is known to consume oil between service intervals. BMW considers a certain rate of consumption normal, but owners should monitor levels closely since consumption often worsens alongside a failing CVV or leaking gaskets.

Low oil level between changes
Blue smoke on acceleration
Oil warning light illuminating
DIY: Low
Turbo Coolant Line Rust and Leakage€300-800 · 100,000-180,000 kmMODERATE

Turbo coolant lines on N55 platforms can rust and leak, particularly at clamp connections. This is less common than the gasket-related leaks but shows up more frequently on cars from salt-belt regions.

Coolant loss
Overheating
Visible rust or wetness around turbo coolant lines
DIY: Moderate
Airbag Inflator Module Recall (Takata)€0-0 · 0-999,999 kmLOW

NHTSA recalls cover certain E90/E92 335i models for faulty Takata airbag inflator modules on the driver side. This is a safety recall and must be verified as completed on any used example.

No warning symptoms; risk of inflator rupture in a collision
DIY: Dealer Only
Electrical System Wiring Recall€0-0 · 0-999,999 kmLOW

NHTSA recalls affect 2006-2011 3 Series including 335i for electrical wiring system faults. Verify recall completion status before purchase.

Intermittent electrical faults
Warning lights
DIY: Dealer Only
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Official Recalls

RecallAirbag - Driver Side Frontal Inflator Module (Takata)

Inflator rupture may send metal fragments toward occupants, causing injury or death

Remedy: Replace airbag inflator module, verify completion via NHTSA VIN lookup
RecallElectrical System - Wiring

Wiring fault may cause electrical system malfunction or fire risk

Remedy: Dealer inspection and wiring repair, verify completion via NHTSA VIN lookup
RecallElectrical System (1-Series and 3-Series)

Electrical fault affecting vehicle safety systems

Remedy: Dealer repair, check recall completion status before purchase
RecallAirbag - Driver Side Frontal Inflator Module (3 Series Sedan)

Takata inflator rupture risk, serious injury or fatality potential

Remedy: Inflator module replacement at no cost, confirm completed at dealership

Buying Checklist

Run the VIN through the NHTSA recall database and confirm all open recalls, especially the Takata airbag campaigns, are completed
Inspect valve cover gasket area and spark plug wells for oil contamination and evidence of leaks
Check oil filter housing area for oil or coolant staining; request recent OFHG replacement records
Ask for full oil change history and verify intervals were no longer than 8,000-10,000 km using OEM-spec 5W-30 LL-01
Do a cold-start listen for lower-engine knocking that could indicate rod bearing wear
Check coolant level and condition; inspect turbo coolant lines for rust, cracking, or wetness at clamp ends
If comparing 335i, 535i, and 335is/M235i examples, ask for the engine build date, since later production benefited from a revised rod bearing spec

Service Reality

Community oil interval8,000 km
Oil specificationBMW LL-01 5W-30 fully synthetic
Est. ownership cost (2yr)€3,500-7,500 over 3 years, covering routine maintenance, typical oil leak repairs (valve cover and oil filter housing gaskets), and a contingency allowance for rod bearing inspection or replacement on a 100,000+ km example
Real mix fuel consumption9.3 L/100km

Strong Points

✓Significantly more reliable than the N54 it replaced, with fewer high-pressure fuel pump and injector issues
✓Single twin-scroll turbo setup is simpler and more robust than N54's twin-turbo configuration
✓Strong community support with well-documented DIY repair procedures
✓OEM parts availability is excellent across the E90/E92 platform
✓Well-maintained examples with documented oil changes can be long-lived daily drivers

Also Found In

BMW 135i (E82/E88)BMW 535i (F10)BMW 535i GT (F07)BMW X3 xDrive35i (F25)BMW 740i (F01)BMW Z4 sDrive35i (E89)BMW M235i / M240i (F22/F23)BMW M2 (F87)

Time Bomb Parts Inspect Proactively

Rod Bearings
Inspect oil for metal contamination; replace bearings preventively if history is unknown
100,000 km
Valve Cover Gasket
Inspect at every oil change; replace at first sign of leakage to prevent misfires
80,000 km
Oil Filter Housing Gasket
Replace proactively if not already done; inspect for oil/coolant mixing
100,000 km
Crankcase Ventilation Valve (CVV)
Inspect for cracking or hardness; replace if oil consumption is elevated
90,000 km
Turbo Coolant Lines
Inspect clamps and hose ends for rust and cracking, especially on salt-belt cars
120,000 km

Tuning Risk If This Example Has Been Modified

MODERATE
Signs of modification
•Aluminum aftermarket charge pipe replacing the factory plastic unit, one of the most common early mods on this platform even on otherwise stock cars
•Aftermarket downpipe (catted or catless) once the car moves past a basic Stage 1 flash
•JB4 piggyback module wired into the OBD-II port or tucked under the dash, since JB4 is widely used on the N55 alongside or instead of a full ECU flash
•MHD Wi-Fi adapter or Bootmod3-paired hardware in the glovebox or center console
•Upgraded intercooler on cars pushing toward or past the stock single-turbo ceiling (roughly the mid 300s wheel-horsepower range per community consensus)
•Colder-rated spark plugs or fresher-than-expected ignition coils, since misfire issues after a tune are a known trigger for replacing these early
Can this be hidden before a sale?

MHD Flasher and Bootmod3 can return the DME to a genuine factory-equivalent map without needing a prior stock backup, using the same reference data a dealer tool would use, so a stock-reading OBD scan after a reflash is not proof the car was never tuned. JB4, a very common choice on the N55, is a piggyback rather than a flash: forum discussion around JB4's own map settings confirms owners routinely keep a dedicated 'logging only, tune disabled' mode specifically to run before taking the car to a dealer, and the module itself can simply be unplugged and removed before a sale, leaving no ECU-side trace at all.

Physical checks that still work, even after a reflash
•Aftermarket aluminum charge pipe still fitted even though the tune shows stock, since this is rarely swapped back to the original plastic piece for a sale and is considered a sensible upgrade even on stock cars
•Aftermarket downpipe or intercooler still physically installed despite a stock-reading ECU
•Wastegate rattle at cold start or idle that is more pronounced than typical for the mileage; community sources note tuning makes existing rattle more noticeable even though it also occurs on stock cars
•OBD port wear or a spliced/taped connector near the DME consistent with a piggyback module having been installed and later removed
•Recently replaced spark plugs or coils with no corresponding service record, often done proactively after tuning to prevent WOT misfires
Weak points if pushed
Factory plastic charge pipe
Reported across multiple N55-specific sources as the first part to crack or split under raised boost; commonly the first supporting mod recommended before any Stage 1 tune
Stage 1
Wastegate actuator/linkage
The single twin-scroll turbo's wastegate develops play and rattles with age; tuning does not appear to cause this outright but is described as making existing rattle more noticeable and, per some tuning software notes, adjustable via wastegate duty cycle settings to reduce it
Any tuned stage, more noticeable at Stage 2+
Stock single turbo
Community consensus places the stock turbo's realistic ceiling in roughly the 340 to 370 wheel-horsepower range; power goals beyond that require a turbo upgrade rather than more tuning of the stock hardware
Stage 2+ / turbo upgrade territory
HPFP and injectors
Improved over the N54's version and less prone to sudden failure, but still described as a known weak spot, especially on older/higher-mileage examples pushed with a tune
Stage 2+
Makes these known issues worse
Charge Pipe FailureWastegate RattleHigh-Pressure Fuel Pump Failure
Supporting mods and risk

This is explicitly discussed in N55-specific tuning guides: a Stage 1 flash tune (JB4, MHD, or Bootmod3) on an otherwise stock car is generally treated as low-risk, since the stock turbo and fueling can absorb it. The recommended order before chasing more power is a charge pipe upgrade, then intercooler and downpipe for Stage 2, with plugs/coils addressed proactively. A car showing Stage 2 power claims without an upgraded charge pipe, downpipe, or intercooler is a meaningfully riskier buy than one built in that order, since the factory charge pipe in particular is described as failing quickly under sustained higher boost.

This profile reflects consensus from JB4tech, Bimmerfest, and several N55-focused specialist shop and tuning-parts write-ups, not manufacturer-confirmed limits. Boost and power figures vary by fuel octane, turbo variant (PWG vs EWG), and individual car condition. Treat any suspected tuned or previously tuned example as needing a full pre-purchase inspection (boost leak test, charge pipe and downpipe visual check, cold-start listen for wastegate rattle) rather than relying on an OBD scan alone.

Buying Advice

The N55 is a meaningful reliability step up from the N54, but it is not a trouble-free engine. Oil leaks from the valve cover and oil filter housing gaskets are a matter of when, not if. Rod bearing wear is a legitimate concern on high-mileage or poorly maintained examples, so full service history is non-negotiable. Budget €800-1,500 upfront for deferred maintenance on any used example and avoid cars with no documented oil change records. If the recalls are unresolved, walk away until the seller can confirm completion.

Community Sentiment

Cautiously positive. Owners appreciate the N55 as a more refined and slightly more reliable alternative to the N54, but acknowledge it is still a BMW inline-six with characteristic oil leak tendencies and a real rod bearing risk at higher mileage. Most long-term owners treat preventive maintenance as mandatory, not optional.

Frequently Asked Questions

// 22 logged
❯How reliable is the BMW 335i N55?

The BMW 335i N55 has a reliability score of 62/100, rated "SOLID". Better than N54, but still leaks

❯What are the common problems with the N55?

The most frequently reported issues are Valve Cover Gasket Oil Leak, Oil Filter Housing Gasket (OFHG) Leak, Rod Bearing Wear, Crankcase Ventilation Valve (CVV) / Oil Separator Failure, among others. See the Known Issues section above for symptoms, affected mileage, and repair costs.

❯Does the N55 have valve cover gasket oil leak problems?

Yes, this is a documented issue on the N55, typically appearing around 60,000-120,000 km. The valve cover gasket is a well-documented failure point on the N55. Oil leaks from the gasket can drip onto hot exhaust components and cause misfires when oil enters spark plug wells. Forum data confirms failures as early as 47,000 miles on some units. Typical repair cost: €300-700. DIY difficulty: Moderate.

❯Does the N55 have oil filter housing gasket (ofhg) leak problems?

Yes, this is a documented issue on the N55, typically appearing around 80,000-160,000 km. The oil filter housing gasket is prone to leaking on the N55, allowing oil and coolant to mix or escape externally. This is a recurring service item across the platform, most often surfacing during a coolant top-up or oil leak inspection. Typical repair cost: €400-900. DIY difficulty: Moderate.

❯Does the N55 have rod bearing wear problems?

Yes, this is a documented issue on the N55, typically appearing around 100,000-180,000 km. N55 engines can suffer spun or worn rod bearings at higher mileages, particularly on earlier production units and cars with extended oil change intervals. BMW revised the bearing specification during the production run, which appears to have reduced but not eliminated the issue on later-built engines. Typical repair cost: €1,500-4,000. DIY difficulty: Expert.

❯Does the N55 have crankcase ventilation valve (cvv) / oil separator failure problems?

Yes, this is a documented issue on the N55, typically appearing around 80,000-150,000 km. The CVV or oil separator can fail on the N55, leading to increased crankcase pressure, oil consumption, and external oil leaks. This is a common contributor to oil consumption complaints across the platform. Typical repair cost: €200-500. DIY difficulty: Moderate.

❯Does the N55 have oil consumption problems?

Yes, this is a documented issue on the N55, typically appearing around 60,000-150,000 km. The N55 is known to consume oil between service intervals. BMW considers a certain rate of consumption normal, but owners should monitor levels closely since consumption often worsens alongside a failing CVV or leaking gaskets. Typical repair cost: €100-300. DIY difficulty: Low.

❯Does the N55 have turbo coolant line rust and leakage problems?

Yes, this is a documented issue on the N55, typically appearing around 100,000-180,000 km. Turbo coolant lines on N55 platforms can rust and leak, particularly at clamp connections. This is less common than the gasket-related leaks but shows up more frequently on cars from salt-belt regions. Typical repair cost: €300-800. DIY difficulty: Moderate.

❯Is the N55 worth buying used?

The N55 is a meaningful reliability step up from the N54, but it is not a trouble-free engine. Oil leaks from the valve cover and oil filter housing gaskets are a matter of when, not if. Rod bearing wear is a legitimate concern on high-mileage or poorly maintained examples, so full service history is non-negotiable. Budget €800-1,500 upfront for deferred maintenance on any used example and avoid cars with no documented oil change records. If the recalls are unresolved, walk away until the seller can confirm completion.

❯Should I buy a BMW 335i with the N55 engine?

The base 306 hp tune is the most common and cheapest to maintain, and it makes sense as the default choice for most buyers. Do not assume higher output means higher risk here: the 335is and M2 versions actually have stronger internals, forged pistons and rods, specifically because BMW allowed more torque through them. If buying a standard 335i, 535i, or X3 xDrive35i, prioritize a car with full documented oil change history and, where possible, one built after the 2013 rod bearing revision, since bearing wear remains the single biggest catastrophic risk across the whole N55 family regardless of power output.

❯What should I check before buying a used N55?

Before buying, check: Run the VIN through the NHTSA recall database and confirm all open recalls, especially the Takata airbag campaigns, are completed; Inspect valve cover gasket area and spark plug wells for oil contamination and evidence of leaks; Check oil filter housing area for oil or coolant staining; request recent OFHG replacement records; Ask for full oil change history and verify intervals were no longer than 8,000-10,000 km using OEM-spec 5W-30 LL-01; Do a cold-start listen for lower-engine knocking that could indicate rod bearing wear.

❯How many km will a N55 last?

There's no fixed mileage limit, it depends on maintenance. The parts worth budgeting for proactively are: Rod Bearings (100,000 km), Valve Cover Gasket (80,000 km), Oil Filter Housing Gasket (100,000 km), Crankcase Ventilation Valve (CVV) (90,000 km). Engines that clear these checkpoints with documented maintenance commonly continue well beyond typical ownership periods.

❯Is there a recall for the airbag - driver side frontal inflator module (takata) on the N55?

Inflator rupture may send metal fragments toward occupants, causing injury or death Remedy: Replace airbag inflator module, verify completion via NHTSA VIN lookup

❯Is there a recall for the electrical system - wiring on the N55?

Wiring fault may cause electrical system malfunction or fire risk Remedy: Dealer inspection and wiring repair, verify completion via NHTSA VIN lookup

❯Is there a recall for the electrical system (1-series and 3-series) on the N55?

Electrical fault affecting vehicle safety systems Remedy: Dealer repair, check recall completion status before purchase

❯Is there a recall for the airbag - driver side frontal inflator module (3 series sedan) on the N55?

Takata inflator rupture risk, serious injury or fatality potential Remedy: Inflator module replacement at no cost, confirm completed at dealership

❯How much does it cost to maintain a N55?

Estimated ownership cost is €3,500-7,500 over 3 years, covering routine maintenance, typical oil leak repairs (valve cover and oil filter housing gaskets), and a contingency allowance for rod bearing inspection or replacement on a 100,000+ km example, based on known issues and typical service needs.

❯What is the real-world fuel consumption of the N55?

Owners report real-world fuel consumption of around 9.3 L/100km, compared to the official figure of 12.8 L/100km.

❯What oil should I use in a N55, and how often?

Community-reported real-world usage suggests changing oil every 8,000 km using BMW LL-01 5W-30 fully synthetic, often more conservative than the official service schedule.

❯Is it safe to tune or remap the N55?

The N55 is commonly modified, with a moderate risk level when pushed beyond stock. Typical weak points under tuning: Factory plastic charge pipe, Wastegate actuator/linkage, Stock single turbo, HPFP and injectors.

❯What other cars use the N55 engine?

The N55 is also found in: BMW 135i (E82/E88), BMW 535i (F10), BMW 535i GT (F07), BMW X3 xDrive35i (F25), BMW 740i (F01), BMW Z4 sDrive35i (E89), BMW M235i / M240i (F22/F23), BMW M2 (F87).

❯What do owners say about the N55?

Cautiously positive. Owners appreciate the N55 as a more refined and slightly more reliable alternative to the N54, but acknowledge it is still a BMW inline-six with characteristic oil leak tendencies and a real rod bearing risk at higher mileage. Most long-term owners treat preventive maintenance as mandatory, not optional.

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