BMW 3er E90

Widely used four-cylinder diesel with common-rail injection and piezo injectors. The notorious timing chain issue is the central concern: the chain sits at the gearbox side (rear of engine), stretches with irregular maintenance, and can snap — total engine loss. BMW revised the design multiple times (sharp-edged sprockets until 2009, improved from 2010) but never fully resolved it. Metallic rattling on cold start is the warning sign. Second major issue: the high-pressure fuel pump can shed metal shavings throughout the entire fuel system — requiring replacement of injectors, rail, and lines. On the positive side: the engine is economical in daily use (5-6 L/100km real), delivers solid torque from 1,750 rpm, and runs 250,000+ km with proper care. Short oil change intervals (max 15,000 km, better 10,000) and BMW-spec oil (LL-04) are mandatory. Used car purchase: have timing chain condition checked via endoscope or chain tensioner reset value.

• !! Timing chain breaks — known serial defect from 100,000 km

  The N47D20 is notorious for its serial timing chain defect. The rear-mounted timing chain stretches and plastic guide rails break. Chain breakage causes total engine failure. Affected: build years 2007–2015.

  Symptoms: Scraping or rattling noises on cold start from the rear of the engine. The damage often gives no acoustic warning and occurs suddenly.
  3,000–7,000 $
  Ad timing chain kit N47D20timing chain BMW 318d 320d N47chain tensioner N47timing chain N47 11318572503
• !! Water pump defective — overheating risk from 120,000 km

  The N47 water pump fails prematurely. When it does the engine overheats, causing secondary damage to an already vulnerable engine. Preventive replacement is recommended.

  Symptoms: Coolant temperature rises suddenly, coolant loss, engine warning light, in the worst case overheating damage.
  400–1,000 $
  Ad water pump N47D20coolant pump BMW 320d E90 N47
• !! High-pressure pump failure — metal swarf in the system from 200,000 km

  The high-pressure pump can wear internally and introduce metal swarf into the fuel system. Rail, pressure sensor, and all injectors are affected — complete system replacement is necessary.

  Symptoms: Engine goes into limp mode; will not restart; fault code "rail pressure too low"; in the worst case the engine no longer runs
  2,500–6,000 $
  Ad N47 high-pressure fuel pumpBMW CP4 high-pressure fuel pumpBMW 13517616170

+ 6 more engine weaknesses + vehicle weaknesses

The M47TUD20 is the revised version of BMW's first common-rail diesel, producing between 120 and 165 hp depending on the tune. At its core a solid four-cylinder diesel that can easily surpass 300,000 km with proper maintenance. The biggest weakness is the notorious swirl flaps in the intake manifold — when carbon buildup causes them to seize, fragments can enter the combustion chamber and cause catastrophic engine damage. Many workshops recommend preventive removal or regular cleaning beyond 150,000 km. Injectors tend to leak at high mileage, causing rough running and power loss. The crankcase ventilation system and turbo oil return line should also be monitored. When buying, watch for blue or white smoke on cold starts — this points to worn injector seals. Oil change intervals should be kept under 15,000 km; BMW longlife intervals are too generous for this engine.

• !! Timing chain stretches from 155,000 km

  The timing chain can stretch or the chain tensioner can fail. Compared to the N47 the M47 is considered more robust, but timing chain problems occur at high mileages and with neglected maintenance.

  Symptoms: Rattling on cold start from the front of the engine, easing after warm-up. With heavy stretching, engine damage through chain jump.
  800–3,000 $
  Ad Timing chain M47TUD20Chain tensioner BMW 120d E87
• !! Swirl flaps break off and fall into the engine from 100,000 km

  The metal swirl flaps in the intake manifold work loose through carbon deposits and can break off. An ingested flap blade causes immediate total damage to valves and pistons.

  Symptoms: Engine stumbling, sudden severe power loss, loud metallic noise from engine, engine failure.
  150–8,000 $
  Ad Swirl flap delete M47TUIntake manifold M47TUD2011617788459
• !! Cylinder head cracks (M47TU variant) from 180,000 km

  The aluminium cylinder head of the M47TU tends to develop hairline cracks between valve seats and glow plug bores at high mileages. The cause is the different thermal expansion coefficient of the aluminium head and cast iron block.

  Symptoms: White smoke from exhaust, rising oil level through coolant contamination, coolant loss without visible leakage.
  1,500–5,000 $
  Ad Cylinder head M47TUD2011127793204

+ 5 more engine weaknesses + vehicle weaknesses

Widely used four-cylinder diesel with common-rail injection and piezo injectors. The notorious timing chain issue is the central concern: the chain sits at the gearbox side (rear of engine), stretches with irregular maintenance, and can snap — total engine loss. BMW revised the design multiple times (sharp-edged sprockets until 2009, improved from 2010) but never fully resolved it. Metallic rattling on cold start is the warning sign. Second major issue: the high-pressure fuel pump can shed metal shavings throughout the entire fuel system — requiring replacement of injectors, rail, and lines. On the positive side: the engine is economical in daily use (5-6 L/100km real), delivers solid torque from 1,750 rpm, and runs 250,000+ km with proper care. Short oil change intervals (max 15,000 km, better 10,000) and BMW-spec oil (LL-04) are mandatory. Used car purchase: have timing chain condition checked via endoscope or chain tensioner reset value.

• !! Timing chain breaks — known serial defect from 100,000 km

  The N47D20 is notorious for its serial timing chain defect. The rear-mounted timing chain stretches and plastic guide rails break. Chain breakage causes total engine failure. Affected: build years 2007–2015.

  Symptoms: Scraping or rattling noises on cold start from the rear of the engine. The damage often gives no acoustic warning and occurs suddenly.
  3,000–7,000 $
  Ad timing chain kit N47D20timing chain BMW 318d 320d N47chain tensioner N47timing chain N47 11318572503
• !! Water pump defective — overheating risk from 120,000 km

  The N47 water pump fails prematurely. When it does the engine overheats, causing secondary damage to an already vulnerable engine. Preventive replacement is recommended.

  Symptoms: Coolant temperature rises suddenly, coolant loss, engine warning light, in the worst case overheating damage.
  400–1,000 $
  Ad water pump N47D20coolant pump BMW 320d E90 N47
• !! High-pressure pump failure — metal swarf in the system from 200,000 km

  The high-pressure pump can wear internally and introduce metal swarf into the fuel system. Rail, pressure sensor, and all injectors are affected — complete system replacement is necessary.

  Symptoms: Engine goes into limp mode; will not restart; fault code "rail pressure too low"; in the worst case the engine no longer runs
  2,500–6,000 $
  Ad N47 high-pressure fuel pumpBMW CP4 high-pressure fuel pumpBMW 13517616170

+ 6 more engine weaknesses + vehicle weaknesses

The M47TUD20 is the revised version of BMW's first common-rail diesel, producing between 120 and 165 hp depending on the tune. At its core a solid four-cylinder diesel that can easily surpass 300,000 km with proper maintenance. The biggest weakness is the notorious swirl flaps in the intake manifold — when carbon buildup causes them to seize, fragments can enter the combustion chamber and cause catastrophic engine damage. Many workshops recommend preventive removal or regular cleaning beyond 150,000 km. Injectors tend to leak at high mileage, causing rough running and power loss. The crankcase ventilation system and turbo oil return line should also be monitored. When buying, watch for blue or white smoke on cold starts — this points to worn injector seals. Oil change intervals should be kept under 15,000 km; BMW longlife intervals are too generous for this engine.

• !! Timing chain stretches from 155,000 km

  The timing chain can stretch or the chain tensioner can fail. Compared to the N47 the M47 is considered more robust, but timing chain problems occur at high mileages and with neglected maintenance.

  Symptoms: Rattling on cold start from the front of the engine, easing after warm-up. With heavy stretching, engine damage through chain jump.
  800–3,000 $
  Ad Timing chain M47TUD20Chain tensioner BMW 120d E87
• !! Swirl flaps break off and fall into the engine from 100,000 km

  The metal swirl flaps in the intake manifold work loose through carbon deposits and can break off. An ingested flap blade causes immediate total damage to valves and pistons.

  Symptoms: Engine stumbling, sudden severe power loss, loud metallic noise from engine, engine failure.
  150–8,000 $
  Ad Swirl flap delete M47TUIntake manifold M47TUD2011617788459
• !! Cylinder head cracks (M47TU variant) from 180,000 km

  The aluminium cylinder head of the M47TU tends to develop hairline cracks between valve seats and glow plug bores at high mileages. The cause is the different thermal expansion coefficient of the aluminium head and cast iron block.

  Symptoms: White smoke from exhaust, rising oil level through coolant contamination, coolant loss without visible leakage.
  1,500–5,000 $
  Ad Cylinder head M47TUD2011127793204

+ 5 more engine weaknesses + vehicle weaknesses

Widely used four-cylinder diesel with common-rail injection and piezo injectors. The notorious timing chain issue is the central concern: the chain sits at the gearbox side (rear of engine), stretches with irregular maintenance, and can snap — total engine loss. BMW revised the design multiple times (sharp-edged sprockets until 2009, improved from 2010) but never fully resolved it. Metallic rattling on cold start is the warning sign. Second major issue: the high-pressure fuel pump can shed metal shavings throughout the entire fuel system — requiring replacement of injectors, rail, and lines. On the positive side: the engine is economical in daily use (5-6 L/100km real), delivers solid torque from 1,750 rpm, and runs 250,000+ km with proper care. Short oil change intervals (max 15,000 km, better 10,000) and BMW-spec oil (LL-04) are mandatory. Used car purchase: have timing chain condition checked via endoscope or chain tensioner reset value.

• !! Timing chain breaks — known serial defect from 100,000 km

  The N47D20 is notorious for its serial timing chain defect. The rear-mounted timing chain stretches and plastic guide rails break. Chain breakage causes total engine failure. Affected: build years 2007–2015.

  Symptoms: Scraping or rattling noises on cold start from the rear of the engine. The damage often gives no acoustic warning and occurs suddenly.
  3,000–7,000 $
  Ad timing chain kit N47D20timing chain BMW 318d 320d N47chain tensioner N47timing chain N47 11318572503
• !! Water pump defective — overheating risk from 120,000 km

  The N47 water pump fails prematurely. When it does the engine overheats, causing secondary damage to an already vulnerable engine. Preventive replacement is recommended.

  Symptoms: Coolant temperature rises suddenly, coolant loss, engine warning light, in the worst case overheating damage.
  400–1,000 $
  Ad water pump N47D20coolant pump BMW 320d E90 N47
• !! High-pressure pump failure — metal swarf in the system from 200,000 km

  The high-pressure pump can wear internally and introduce metal swarf into the fuel system. Rail, pressure sensor, and all injectors are affected — complete system replacement is necessary.

  Symptoms: Engine goes into limp mode; will not restart; fault code "rail pressure too low"; in the worst case the engine no longer runs
  2,500–6,000 $
  Ad N47 high-pressure fuel pumpBMW CP4 high-pressure fuel pumpBMW 13517616170

+ 6 more engine weaknesses + vehicle weaknesses

Successor to the legendary M57 with aluminum crankcase and piezo injectors. Extremely smooth, powerful, and with proper care a 400,000 km engine. From 204 to 313 hp (330d to 335d xDrive) — in every power level one of the best diesel configurations in BMW's lineup. The ZF 8HP automatic pairs perfectly with the sovereign torque delivery. Weak points are the EGR cooler (same issue as B47, check recall status), DPF with short-distance driving, and the turbochargers — the N57 uses staged bi-turbo charging that becomes wear-prone at high mileages. Injectors typically last 200,000+ km. Buying tip: service history is worth its weight in gold with the N57 — a well-maintained N57 is one of the best used diesel engines, period.

• !! Timing chain breaks / guide rails shatter from 130,000 km

  The N57D30 timing chain can break; plastic guide rails break and block the oil pump. Damaged valves and bearing shells follow. No reliable audible advance warning.

  Symptoms: Rattling or clattering on cold start (warning sign!). Often no advance warning — engine dies suddenly.
  2,000–6,000 $
  Ad timing chain kit N57D30timing chain BMW 530d F10 N57
• !! Connecting rod / main bearing damage at high mileage from 180,000 km

  Main bearings and connecting rod bearings wear from around 150,000–200,000 km. The aluminium crankcase with steel bearing housings has differing thermal expansion coefficients. Bearing shells can spin — catastrophic engine damage.

  Symptoms: Dull knocking or hammering from the engine block under load; oil pressure warning; metallic tapping; engine oil with metallic particles
  3,000–12,000 $
  Ad N57 LagerschalenN57 connecting rod bearingN57D30 main Lager
• !! EGR cooler leak — coolant loss from 120,000 km

  Leaking EGR coolers cause gradual coolant loss. BMW carried out a voluntary service campaign. Overheating from coolant shortage risks a cracked cylinder head. Repair costs without goodwill are very high.

  Symptoms: Gradual coolant drop with no visible external leak; white-blue exhaust smoke; sweet smell inside the cabin; engine warning light; overheating warning
  350–4,000 $
  Ad N57 EGR radiatorN57 EGR-radiatorBMW N57 coolant

+ 7 more engine weaknesses + vehicle weaknesses

The M57TUD30 is the uprated variant of BMW's legendary inline-six diesel with variable turbine geometry, producing up to 286 hp in twin-turbo form. At its core one of the finest six-cylinder diesels ever built — refined, enormously torquey, and long-lasting with proper maintenance. The turbochargers are the main concern: VTG vanes coke up over time, leading to power loss and potentially turbo failure. The twin-turbo version doubles the repair bill. The diesel particulate filter tends to cause issues beyond 180,000 km, especially with frequent short trips. Timing chain and guide rails should be inspected past 200,000 km. Injectors and high-pressure pump are durable with clean fuel supply, but replacement costs are significant. When buying, verify regular oil changes — this engine reacts poorly to neglected maintenance. A well-maintained M57TUD30 is an outstanding long-distance powerplant.

• !! Timing chain stretched / chain tensioner defective from 175,000 km

  As mileage increases the timing chain stretches and the chain tensioner loses its spring force. Broken plastic guide rails send fragments into the oil sump, which can damage the oil pump.

  Symptoms: Rattling or clattering on cold start that improves once warm. Further wear can lead to engine damage.
  1,300–3,000 $
  Ad timing chain kit M57TUD30chain tensioner BMW 335d E90
• !! Swirl flaps break off (known risk) from 150,000 km

  The swirl flaps in the M57TUD30 intake manifold become heavy from carbon and EGR soot deposits and can break off. Metal fragments enter the combustion chamber and destroy valves and pistons.

  Symptoms: Sudden hard engine knock, power loss, blue smoke, engine will not restart.
  150–9,000 $
  Ad swirl flaps Delete M57TUintake manifold M57TUD3011617788459
• !! Swirl flaps — biturbo version from 120,000 km

  The M57TUD30 biturbo retains the familiar swirl flap problems of the M57. Even the reinforced versions after 2004 can develop leaks or stick.

  Symptoms: Hesitation under acceleration, intake tract noise, power loss at part throttle, swirl flap actuator fault code
  200–2,000 $
  Ad swirl flaps M57TUD30 BMW 335dintake manifold 335d E90 M57TU2

+ 7 more engine weaknesses + vehicle weaknesses

Successor to the legendary M57 with aluminum crankcase and piezo injectors. Extremely smooth, powerful, and with proper care a 400,000 km engine. From 204 to 313 hp (330d to 335d xDrive) — in every power level one of the best diesel configurations in BMW's lineup. The ZF 8HP automatic pairs perfectly with the sovereign torque delivery. Weak points are the EGR cooler (same issue as B47, check recall status), DPF with short-distance driving, and the turbochargers — the N57 uses staged bi-turbo charging that becomes wear-prone at high mileages. Injectors typically last 200,000+ km. Buying tip: service history is worth its weight in gold with the N57 — a well-maintained N57 is one of the best used diesel engines, period.

• !! Timing chain breaks / guide rails shatter from 130,000 km

  The N57D30 timing chain can break; plastic guide rails break and block the oil pump. Damaged valves and bearing shells follow. No reliable audible advance warning.

  Symptoms: Rattling or clattering on cold start (warning sign!). Often no advance warning — engine dies suddenly.
  2,000–6,000 $
  Ad timing chain kit N57D30timing chain BMW 530d F10 N57
• !! Connecting rod / main bearing damage at high mileage from 180,000 km

  Main bearings and connecting rod bearings wear from around 150,000–200,000 km. The aluminium crankcase with steel bearing housings has differing thermal expansion coefficients. Bearing shells can spin — catastrophic engine damage.

  Symptoms: Dull knocking or hammering from the engine block under load; oil pressure warning; metallic tapping; engine oil with metallic particles
  3,000–12,000 $
  Ad N57 LagerschalenN57 connecting rod bearingN57D30 main Lager
• !! EGR cooler leak — coolant loss from 120,000 km

  Leaking EGR coolers cause gradual coolant loss. BMW carried out a voluntary service campaign. Overheating from coolant shortage risks a cracked cylinder head. Repair costs without goodwill are very high.

  Symptoms: Gradual coolant drop with no visible external leak; white-blue exhaust smoke; sweet smell inside the cabin; engine warning light; overheating warning
  350–4,000 $
  Ad N57 EGR radiatorN57 EGR-radiatorBMW N57 coolant

+ 7 more engine weaknesses + vehicle weaknesses

The M57TUD30 is the uprated variant of BMW's legendary inline-six diesel with variable turbine geometry, producing up to 286 hp in twin-turbo form. At its core one of the finest six-cylinder diesels ever built — refined, enormously torquey, and long-lasting with proper maintenance. The turbochargers are the main concern: VTG vanes coke up over time, leading to power loss and potentially turbo failure. The twin-turbo version doubles the repair bill. The diesel particulate filter tends to cause issues beyond 180,000 km, especially with frequent short trips. Timing chain and guide rails should be inspected past 200,000 km. Injectors and high-pressure pump are durable with clean fuel supply, but replacement costs are significant. When buying, verify regular oil changes — this engine reacts poorly to neglected maintenance. A well-maintained M57TUD30 is an outstanding long-distance powerplant.

• !! Timing chain stretched / chain tensioner defective from 175,000 km

  As mileage increases the timing chain stretches and the chain tensioner loses its spring force. Broken plastic guide rails send fragments into the oil sump, which can damage the oil pump.

  Symptoms: Rattling or clattering on cold start that improves once warm. Further wear can lead to engine damage.
  1,300–3,000 $
  Ad timing chain kit M57TUD30chain tensioner BMW 335d E90
• !! Swirl flaps break off (known risk) from 150,000 km

  The swirl flaps in the M57TUD30 intake manifold become heavy from carbon and EGR soot deposits and can break off. Metal fragments enter the combustion chamber and destroy valves and pistons.

  Symptoms: Sudden hard engine knock, power loss, blue smoke, engine will not restart.
  150–9,000 $
  Ad swirl flaps Delete M57TUintake manifold M57TUD3011617788459
• !! Swirl flaps — biturbo version from 120,000 km

  The M57TUD30 biturbo retains the familiar swirl flap problems of the M57. Even the reinforced versions after 2004 can develop leaks or stick.

  Symptoms: Hesitation under acceleration, intake tract noise, power loss at part throttle, swirl flap actuator fault code
  200–2,000 $
  Ad swirl flaps M57TUD30 BMW 335dintake manifold 335d E90 M57TU2

+ 7 more engine weaknesses + vehicle weaknesses

The N46B20 is a two-litre four-cylinder with Valvetronic variable valve lift, producing between 129 and 150 hp as the successor to the M54B22. In daily use a pleasantly smooth and economical engine that eliminates the conventional throttle body through continuously variable valve lift. The most well-known weakness is the Valvetronic eccentric shaft — when its bearings wear, rattling and clattering noises appear, and the repair is involved, sometimes requiring cylinder head removal. Timing chain and tensioner should be inspected beyond 150,000 km; a stretched chain makes itself known through rattling on cold starts. The crankcase ventilation system is a known wear item that can cause oil leaks and rough idle when it fails. VANOS solenoid valves become contaminated with extended oil change intervals. When buying used, listen for clean idle and ask about oil consumption — more than 0.5 litres per 1,000 km is a warning sign. Overall a reliable engine when the known wear items are kept in check.

• !! Timing chain stretched / chain tensioner defective from 110,000 km

  The timing chain stretches prematurely due to a faulty chain tensioner. Plastic guide rails become brittle and break. Engine damage from chain jump is possible.

  Symptoms: Rattling or clattering on cold start in the first few seconds, which improves or worsens as the engine warms up.
  600–1,200 $
  Ad timing chain N46B20chain tensioner BMW 318i E46 E9011311742042
• !! Valvetronic eccentric shaft / actuator motor defective from 150,000 km

  The Valvetronic actuator motor or eccentric shaft fails at around 150,000 km. Fault code 2A67 is typical. The engine runs but without variable valve lift control — increased fuel consumption, limp mode.

  Symptoms: Judder at 2,000 rpm; rough cold start; increased fuel consumption; engine stumbling when pulling away; fault code 2A67
  400–1,200 $
  Ad N46 valvetronic actuator motorBMW 11377507804N46 Exzenterwelle
• ! VANOS solenoid valve defective from 90,000 km

  The VANOS solenoid valves wear and cause rpm fluctuations, power loss, and starting difficulties, especially at low revs.

  Symptoms: Rpm fluctuations at idle, power loss at low revs, occasional starting difficulties.
  300–850 $
  Ad VANOS solenoid valve N46VANOS solenoid valve BMW 318i 320i

+ 6 more engine weaknesses + vehicle weaknesses

The N43B20 is a two-litre naturally aspirated engine with direct petrol injection and stratified charge operation, producing between 143 and 170 hp depending on the variant. Technically ambitious but in practice one of the most troublesome BMW petrol engines of its era. The high-pressure fuel pump is the Achilles heel — failure leaves the engine in limp mode or dead entirely. Injectors also wear faster than with conventional port injection and cost around 250 euros each to replace. The timing chain tends to stretch with inadequate oil maintenance, announcing itself through rattling on cold starts. The stratified charge system additionally requires a complex NOx storage catalyst that is sensitive to fuel quality. Lambda sensors and camshaft position sensors are among the frequently replaced wear items. This engine was only sold in European markets. When buying, listen for smooth idle — fluctuations often point to injector problems. Short oil change intervals under 12,000 km are essential.

• !! Timing chain stretched — critical issue from 80,000 km

  The N43B20 has a known timing chain problem. The chain tensioner fails prematurely and plastic guide rails break. BMW published an improved tensioner in October 2016 (11318685091), but the underlying issue remains.

  Symptoms: Rattling or clattering on cold start and during load changes. In advanced stages, engine damage through chain jump or breakage.
  800–2,500 $
  Ad chain tensioner N43B20 11318685091timing chain kit N43B20
• !! Piezo injectors wearing out — full set replacement required from 100,000 km

  The stratified-charge piezo injectors wear from around 80,000–100,000 km. Failure requires complete replacement of all four injectors. Calibration values must be programmed into the control unit.

  Symptoms: Hesitation and misfires especially after cold start; misfires in specific cylinders; rough idle; fuel smell; improvement once engine is warm
  1,200–3,800 $
  Ad N43 fuel injectorBMW N43B20 fuel injectorN43 Piezo fuel injector13538616079
• !! High-pressure pump defective from 150,000 km

  The direct injection high-pressure pump fails and causes extended cold starts or hesitation under full load. Fault codes 2FBF, 2FBE, 29DC, 29E2 are typical.

  Symptoms: Very long cold start (several seconds), hesitation under hard acceleration, fault memory entry for fuel pressure.
  450–900 $
  Ad high-pressure fuel pump N43B20high-pressure fuel pump BMW 318i N43

+ 5 more engine weaknesses + vehicle weaknesses

The N46B20 is a two-litre four-cylinder with Valvetronic variable valve lift, producing between 129 and 150 hp as the successor to the M54B22. In daily use a pleasantly smooth and economical engine that eliminates the conventional throttle body through continuously variable valve lift. The most well-known weakness is the Valvetronic eccentric shaft — when its bearings wear, rattling and clattering noises appear, and the repair is involved, sometimes requiring cylinder head removal. Timing chain and tensioner should be inspected beyond 150,000 km; a stretched chain makes itself known through rattling on cold starts. The crankcase ventilation system is a known wear item that can cause oil leaks and rough idle when it fails. VANOS solenoid valves become contaminated with extended oil change intervals. When buying used, listen for clean idle and ask about oil consumption — more than 0.5 litres per 1,000 km is a warning sign. Overall a reliable engine when the known wear items are kept in check.

• !! Timing chain stretched / chain tensioner defective from 110,000 km

  The timing chain stretches prematurely due to a faulty chain tensioner. Plastic guide rails become brittle and break. Engine damage from chain jump is possible.

  Symptoms: Rattling or clattering on cold start in the first few seconds, which improves or worsens as the engine warms up.
  600–1,200 $
  Ad timing chain N46B20chain tensioner BMW 318i E46 E9011311742042
• !! Valvetronic eccentric shaft / actuator motor defective from 150,000 km

  The Valvetronic actuator motor or eccentric shaft fails at around 150,000 km. Fault code 2A67 is typical. The engine runs but without variable valve lift control — increased fuel consumption, limp mode.

  Symptoms: Judder at 2,000 rpm; rough cold start; increased fuel consumption; engine stumbling when pulling away; fault code 2A67
  400–1,200 $
  Ad N46 valvetronic actuator motorBMW 11377507804N46 Exzenterwelle
• ! VANOS solenoid valve defective from 90,000 km

  The VANOS solenoid valves wear and cause rpm fluctuations, power loss, and starting difficulties, especially at low revs.

  Symptoms: Rpm fluctuations at idle, power loss at low revs, occasional starting difficulties.
  300–850 $
  Ad VANOS solenoid valve N46VANOS solenoid valve BMW 318i 320i

+ 6 more engine weaknesses + vehicle weaknesses

The N43B20 is a two-litre naturally aspirated engine with direct petrol injection and stratified charge operation, producing between 143 and 170 hp depending on the variant. Technically ambitious but in practice one of the most troublesome BMW petrol engines of its era. The high-pressure fuel pump is the Achilles heel — failure leaves the engine in limp mode or dead entirely. Injectors also wear faster than with conventional port injection and cost around 250 euros each to replace. The timing chain tends to stretch with inadequate oil maintenance, announcing itself through rattling on cold starts. The stratified charge system additionally requires a complex NOx storage catalyst that is sensitive to fuel quality. Lambda sensors and camshaft position sensors are among the frequently replaced wear items. This engine was only sold in European markets. When buying, listen for smooth idle — fluctuations often point to injector problems. Short oil change intervals under 12,000 km are essential.

• !! Timing chain stretched — critical issue from 80,000 km

  The N43B20 has a known timing chain problem. The chain tensioner fails prematurely and plastic guide rails break. BMW published an improved tensioner in October 2016 (11318685091), but the underlying issue remains.

  Symptoms: Rattling or clattering on cold start and during load changes. In advanced stages, engine damage through chain jump or breakage.
  800–2,500 $
  Ad chain tensioner N43B20 11318685091timing chain kit N43B20
• !! Piezo injectors wearing out — full set replacement required from 100,000 km

  The stratified-charge piezo injectors wear from around 80,000–100,000 km. Failure requires complete replacement of all four injectors. Calibration values must be programmed into the control unit.

  Symptoms: Hesitation and misfires especially after cold start; misfires in specific cylinders; rough idle; fuel smell; improvement once engine is warm
  1,200–3,800 $
  Ad N43 fuel injectorBMW N43B20 fuel injectorN43 Piezo fuel injector13538616079
• !! High-pressure pump defective from 150,000 km

  The direct injection high-pressure pump fails and causes extended cold starts or hesitation under full load. Fault codes 2FBF, 2FBE, 29DC, 29E2 are typical.

  Symptoms: Very long cold start (several seconds), hesitation under hard acceleration, fault memory entry for fuel pressure.
  450–900 $
  Ad high-pressure fuel pump N43B20high-pressure fuel pump BMW 318i N43

+ 5 more engine weaknesses + vehicle weaknesses

BMW's first in-house four-cylinder turbo for the mid-range — the farewell to six cylinders in the 320i/328i. Timing chain and guide rails are the main weakness: BMW extended the warranty in 2015 (7 years/100,000 km) and revised the chain design multiple times. Metallic rattling on cold start should be investigated immediately. The electric water pump fails without warning — preventive replacement at 80,000-100,000 km saves a tow truck. Oil filter housing gasket becomes porous and can mix oil with coolant in worst case. Despite the weaknesses, a refined engine: quiet, good mid-range pull, economical (7-8 L/100km real). Manual transmission is the most durable combination. Replaced by the B48 from 2015.

• !! Timing chain and oil pump chain from 50,000 km

  The best-known weak point of the N20. The timing chain and oil pump chain stretch; the chain tensioner fails. BMW offered an extended warranty (7 years/100,000 km) for pre-2015 models.

  Symptoms: Rattling on start, engine warning light, sudden power loss, in extreme cases engine damage
  2,200–4,000 $
  Ad BMW N20 timing chainBMW N20 chain tensioner11318648732BMW N20 oil pumpnkette
• !! Electric water pump failure from 90,000 km

  The electric water pump fails, risking overheating. A BMW-typical problem across all engines with electric coolant pumps since the N52 generation.

  Symptoms: Overheating warning, temperature gauge rises quickly, coolant warning
  400–900 $
  Ad BMW N20 water pump11517632426BMW elektrische water pump
• !! Oil pump chain / oil pump sprocket defective from 80,000 km

  On the N20 the oil pump sprocket can wear prematurely or the oil pump chain can break. In documented cases (50,000 km) an internal drive component failure caused complete oil pump failure — catastrophic engine damage.

  Symptoms: Whistling noise that increases with rpm; oil pressure warning; metallic rushing from the engine bay; unusual vibrations
  1,500–4,000 $
  Ad BMW N20 oil pumpBMW N20 oil pumpnketteBMW N20 chainntrieb

+ 7 more engine weaknesses + vehicle weaknesses

The N52B25 is a 2.5-litre inline six with a magnesium-aluminium composite crankcase and Valvetronic, producing between 177 and 218 hp depending on the power level. One of the last great BMW naturally aspirated engines and for many enthusiasts the epitome of silky-smooth six-cylinder character. In daily use refined, eager to rev, and very durable with proper care. The most common weakness is the oil filter housing gasket, which hardens over time and causes oil leaks — a relatively inexpensive repair that should not be ignored. VANOS solenoid valves become contaminated with extended change intervals, causing rough idle and power loss. The crankcase ventilation system is designed as a wear item and should be replaced when symptoms like oil mist or fluctuating idle appear. Valve stem seals can harden at high mileage, leading to slight oil consumption. The magnesium crankcase is more sensitive to overheating than full aluminium — check the cooling system regularly for leaks. Overall an excellent engine that causes few worries when oil maintenance is kept up.

• !! Electric water pump defective from 120,000 km

  The N52 electric water pump is a known wear item. When it fails the engine overheats quickly. Recommended: preventive replacement when any abnormalities appear or from around 100,000 km.

  Symptoms: Coolant temperature gauge rises quickly, coolant loss, audible pump malfunction, engine overheating.
  500–800 $
  Ad water pump N52B25 elektrischcoolant pump BMW 325i E90 N52
• !! Eccentric shaft sensor (Valvetronic) failure from 130,000 km

  The eccentric shaft sensor on the N52B25 Valvetronic system fails sporadically. Fuel consumption jumps sharply by 30–35%; the sensor costs approximately €315 new from BMW.

  Symptoms: Sporadic eccentric shaft sensor fault code; fuel consumption jumps from ~10 to ~13.5 L/100 km; power loss; whistling noise under acceleration
  50–350 $
  Ad N52 ExzenterwellensensorBMW 11377524879Valvetronic sensor N52
• !! Oil filter housing gasket leaking — oil in coolant from 160,000 km

  The seals in the oil-coolant heat exchanger inside the oil filter housing become porous and allow oil into the coolant. Affects N52, N53, and N54 equally. Always replace both seals at the same time.

  Symptoms: Oil film on the coolant surface; oily-looking oil filler cap; no white smoke or visible fluid loss despite apparent head gasket symptoms
  50–400 $
  Ad N52 oil filter housing gasketBMW 11427509657oil filter housing gasket N52

+ 7 more engine weaknesses + vehicle weaknesses

The N52B25 is a 2.5-litre inline six with a magnesium-aluminium composite crankcase and Valvetronic, producing between 177 and 218 hp depending on the power level. One of the last great BMW naturally aspirated engines and for many enthusiasts the epitome of silky-smooth six-cylinder character. In daily use refined, eager to rev, and very durable with proper care. The most common weakness is the oil filter housing gasket, which hardens over time and causes oil leaks — a relatively inexpensive repair that should not be ignored. VANOS solenoid valves become contaminated with extended change intervals, causing rough idle and power loss. The crankcase ventilation system is designed as a wear item and should be replaced when symptoms like oil mist or fluctuating idle appear. Valve stem seals can harden at high mileage, leading to slight oil consumption. The magnesium crankcase is more sensitive to overheating than full aluminium — check the cooling system regularly for leaks. Overall an excellent engine that causes few worries when oil maintenance is kept up.

• !! Electric water pump defective from 120,000 km

  The N52 electric water pump is a known wear item. When it fails the engine overheats quickly. Recommended: preventive replacement when any abnormalities appear or from around 100,000 km.

  Symptoms: Coolant temperature gauge rises quickly, coolant loss, audible pump malfunction, engine overheating.
  500–800 $
  Ad water pump N52B25 elektrischcoolant pump BMW 325i E90 N52
• !! Eccentric shaft sensor (Valvetronic) failure from 130,000 km

  The eccentric shaft sensor on the N52B25 Valvetronic system fails sporadically. Fuel consumption jumps sharply by 30–35%; the sensor costs approximately €315 new from BMW.

  Symptoms: Sporadic eccentric shaft sensor fault code; fuel consumption jumps from ~10 to ~13.5 L/100 km; power loss; whistling noise under acceleration
  50–350 $
  Ad N52 ExzenterwellensensorBMW 11377524879Valvetronic sensor N52
• !! Oil filter housing gasket leaking — oil in coolant from 160,000 km

  The seals in the oil-coolant heat exchanger inside the oil filter housing become porous and allow oil into the coolant. Affects N52, N53, and N54 equally. Always replace both seals at the same time.

  Symptoms: Oil film on the coolant surface; oily-looking oil filler cap; no white smoke or visible fluid loss despite apparent head gasket symptoms
  50–400 $
  Ad N52 oil filter housing gasketBMW 11427509657oil filter housing gasket N52

+ 7 more engine weaknesses + vehicle weaknesses

The 258 hp top version of the N52 is one of the last large high-revving naturally aspirated engines from BMW: a magnesium-aluminium composite block that defines the class through extreme smoothness and a willingness to rev that drivers describe as 'like a sewing machine' — so even and effortless in its climb. Compared to the N54 turbo it sounds cleaner and more natural, without turbo hiss; instead a clear naturally aspirated note that fills out with increasing revs. Cold-start behaviour is impeccable; in daily use it runs nearly maintenance-free. Typical weaknesses: electric water pump (fails without warning, 80,000–150,000 km, preventive replacement recommended), Valvetronic eccentric shaft sensor (fault code, limp mode), VANOS solenoids with sludge build-up. Buying tip: check service history, as missed oil changes can permanently impair VANOS function.

• !! Electric water pump defective from 120,000 km

  The N52 electric water pump is a known wear item. When it fails the engine overheats quickly. Recommended: preventive replacement when any abnormalities appear or from around 100,000 km.

  Symptoms: Coolant temperature gauge rises quickly, coolant loss, audible pump malfunction, engine overheating.
  600–1,200 $
  Ad water pump N52B30 elektrischcoolant pump BMW 330i E90 N52Elektrische water pump 11517632426thermostat 11537549476
• !! Oil filter housing gasket — oil into coolant from 130,000 km

  The gasket between the oil filter housing and the engine block ages and becomes porous, allowing oil into the coolant. Symptoms resemble a head gasket failure. Early replacement of both seals is recommended.

  Symptoms: Oil film on the coolant; discoloured oil filler cap; coolant slightly foamy or brownish; no white exhaust smoke — a key differentiator from head gasket damage
  150–500 $
  Ad N52 oil filter housing gasketN52 oil filter housing gasketBMW N52 Ölwärmetauscher gasketoil separator 11617531423
• !! Eccentric shaft sensor (Valvetronic) failure from 150,000 km

  The Valvetronic eccentric shaft sensor fails due to moisture and ageing. Fault code 2A31 is typical. The sensor costs approximately €275; installation requires opening the cam cover.

  Symptoms: Rough idle; severe judder with light throttle input; increased fuel consumption (up to +30%); fault code 2A31; engine runs better with the sensor disconnected
  200–800 $
  Ad N52 ExzenterwellensensorN52B30 Exzenterwellen-sensor 11377527016BMW Valvetronic sensor 2A31

+ 6 more engine weaknesses + vehicle weaknesses

The N53B25 is a 2.5-litre inline six with direct petrol injection as the successor to the port-injected N52B25, producing between 190 and 218 hp depending on the tune. The switch to direct injection brought slightly better efficiency but also significantly more trouble spots. The high-pressure pump is the central weakness — failure means the engine will not start or runs in limp mode only. Piezo injectors are sensitive and cost well over 200 euros each; with six of them the bill adds up quickly. Unlike the N52, the N53 operates partly in lean-burn mode, requiring a NOx storage catalyst that is sensitive to fuel quality. Spark plugs need more frequent replacement than on the port-injection predecessor. Timing chain and VANOS system are fundamentally solid but benefit from consistent oil maintenance. The engine character is similarly refined to the N52, even slightly stronger at low revs. When buying, specifically ask about the injection system service history and listen for clean cold starts — hesitation or stumbling during cranking are typical warning signs.

• !! High-pressure pump defective from 120,000 km

  The direct injection high-pressure pump fails and causes extended cold starts or hesitation under full load. Fault codes 2FBF, 2FBE in the fault memory are typical.

  Symptoms: Very extended cold start, hesitation under hard acceleration, fault memory entry for fuel pressure.
  450–10,000 $
  Ad high-pressure fuel pump N53B25BMW 523i N53 fuel pump
• !! Piezo injectors defective (chronic issue) from 80,000 km

  The N53B25 piezo direct injectors are chronically unreliable. Injectors with an index below 09 fail particularly early. Piecemeal replacement gives unreliable results; index-11 injectors are the most stable version.

  Symptoms: Engine stumbling and hesitation, rough cold start, power loss, engine warning message, engine cutting out when lifting off the throttle.
  2,000–2,300 $
  Ad Piezo fuel injector N53B25N53 fuel injector Index 1113537589048
• !! NOx catalyst ageing and NOx sensor failure from 100,000 km

  The NOx sensor fails regularly, causing the ECU to abandon the fuel-efficient stratified charge mode. The NOx catalyst ages and must be replaced. Costs: NOx sensor ~€600, NOx cat >€2,000.

  Symptoms: Significantly increased fuel consumption, fault code 30E9 (NOx catalyst ageing), engine warning light.
  500–2,500 $
  Ad NOx sensor N53NOx catalytic converter BMW 523i N53

+ 6 more engine weaknesses + vehicle weaknesses

The 258 hp top version of the N52 is one of the last large high-revving naturally aspirated engines from BMW: a magnesium-aluminium composite block that defines the class through extreme smoothness and a willingness to rev that drivers describe as 'like a sewing machine' — so even and effortless in its climb. Compared to the N54 turbo it sounds cleaner and more natural, without turbo hiss; instead a clear naturally aspirated note that fills out with increasing revs. Cold-start behaviour is impeccable; in daily use it runs nearly maintenance-free. Typical weaknesses: electric water pump (fails without warning, 80,000–150,000 km, preventive replacement recommended), Valvetronic eccentric shaft sensor (fault code, limp mode), VANOS solenoids with sludge build-up. Buying tip: check service history, as missed oil changes can permanently impair VANOS function.

• !! Electric water pump defective from 120,000 km

  The N52 electric water pump is a known wear item. When it fails the engine overheats quickly. Recommended: preventive replacement when any abnormalities appear or from around 100,000 km.

  Symptoms: Coolant temperature gauge rises quickly, coolant loss, audible pump malfunction, engine overheating.
  600–1,200 $
  Ad water pump N52B30 elektrischcoolant pump BMW 330i E90 N52Elektrische water pump 11517632426thermostat 11537549476
• !! Oil filter housing gasket — oil into coolant from 130,000 km

  The gasket between the oil filter housing and the engine block ages and becomes porous, allowing oil into the coolant. Symptoms resemble a head gasket failure. Early replacement of both seals is recommended.

  Symptoms: Oil film on the coolant; discoloured oil filler cap; coolant slightly foamy or brownish; no white exhaust smoke — a key differentiator from head gasket damage
  150–500 $
  Ad N52 oil filter housing gasketN52 oil filter housing gasketBMW N52 Ölwärmetauscher gasketoil separator 11617531423
• !! Eccentric shaft sensor (Valvetronic) failure from 150,000 km

  The Valvetronic eccentric shaft sensor fails due to moisture and ageing. Fault code 2A31 is typical. The sensor costs approximately €275; installation requires opening the cam cover.

  Symptoms: Rough idle; severe judder with light throttle input; increased fuel consumption (up to +30%); fault code 2A31; engine runs better with the sensor disconnected
  200–800 $
  Ad N52 ExzenterwellensensorN52B30 Exzenterwellen-sensor 11377527016BMW Valvetronic sensor 2A31

+ 6 more engine weaknesses + vehicle weaknesses

The N53B30 is the larger-displacement variant of the N53 family with three litres and between 258 and 272 hp depending on the tune. Technically it shares the stratified direct injection and all associated weaknesses with the smaller N53B25 — high-pressure pump and piezo injectors remain the critical components. Due to higher output and larger displacement, injection system faults tend to manifest earlier because components are under greater stress. The NOx storage catalyst is sensitive to high-sulphur fuel and can cause issues with frequent short-distance driving. On the positive side, it offers effortless pull across the entire rev range and typical BMW six-cylinder refinement. Cooling system components like water pump and thermostat are predictable wear items due around 100,000 km. When buying, always run a diagnostic scan — many injection problems leave fault codes before they become noticeable. A specimen with complete service history and short oil change intervals is worth its weight in gold.

• !! Piezo injectors defective (index-dependent) from 80,000 km

  As with the N53B25, the N53B30 piezo injectors fail frequently, especially those with an index below 09. The unit price of new index-11 injectors was recently €290–370; nationwide supply shortages occurred.

  Symptoms: Hesitation and misfires, hard acceleration surges, extended cold start (4–5 seconds), engine warning.
  2,000–3,000 $
  Ad Piezo fuel injector N53B30N53B30 fuel injector Index 1113537589048
• !! High-pressure pump defective from 120,000 km

  The direct injection high-pressure pump fails and causes extended cold starts or hesitation under full load. Fault codes 2FBF, 2FBE are typical. Specialist workshop repair ~€400; BMW >€2,000.

  Symptoms: Very extended cold start (several seconds), hesitation under hard acceleration, fault memory entry for fuel pressure.
  450–1,500 $
  Ad high-pressure fuel pump N53B30BMW 330i E90 N53 fuel pump
• !! NOx catalyst ageing and NOx sensor failure from 100,000 km

  The NOx sensor fails regularly. The NOx catalyst ages and must be replaced. Costs: NOx sensor ~€600, NOx cat >€2,000. Typical fault code 30E9.

  Symptoms: Significantly increased fuel consumption (no more stratified charge mode), fault code 30E9 (NOx catalyst ageing), engine warning light.
  750–2,500 $
  Ad NOx sensor N53B30NOx catalytic converter BMW 330i N53

+ 6 more engine weaknesses + vehicle weaknesses

BMW's first production twin-turbo straight-six — two small Garrett turbos instead of a single large twin-scroll as on the N55 successor. At idle a quiet metallic whisper; from 3,000 rpm the twin-turbo thrust arrives with a characteristic whistle the N55 doesn't have. No Valvetronic — boost pressure instead of variable valve lift. The high-pressure pump (HPFP) is the N54 issue: if it fails while driving, the engine stops. BMW carried out several recalls but never fully resolved the problem. Piezo injectors must be brought to the latest revision. Wastegate rattle on cold start is cosmetic; turbo bearing damage from neglected oil supply is not. Oil changes every 7,500 km, never BMW Longlife. Let the engine idle for 30 seconds after hard use — the turbos will thank you. Tuning: Stage 1 via software brings 400+ hp; well-built examples with 600+ hp are documented. Those who maintain the N54 get the most exciting BMW six-cylinder of its generation.

• !! High-pressure fuel pump (HPFP) failure from 80,000 km

  A notorious problem on the first BMW turbocharged straight-six. The high-pressure pump loses delivery pressure and the engine goes into limp mode. Build years 2006–2010 most affected; several revisions made.

  Symptoms: Hesitation, power loss, engine warning, engine stalls, extended cranking
  450–1,500 $
  Ad BMW N54 high-pressure fuel pumpBMW N54 high-pressure fuel pump13517616170
• !! Injector failure (index < 10) from 90,000 km

  Piezo injectors from early revisions (index 1–9) are prone to failure. Misfires, rough running. Complete set per bank must be replaced.

  Symptoms: Misfires, rough running, engine warning, elevated emissions
  1,200–3,300 $
  Ad BMW N54 fuel injectorBMW N54 fuel injector13537585261
• !! Turbocharger bearing failure from 150,000 km

  Both turbochargers can suffer bearing damage from insufficient oil supply, blocked return lines, or hot shutdown after full-load driving. Metal swarf in the oil, risk of engine damage.

  Symptoms: Blue smoke from the exhaust, oil in the intercooler and intake tract, whistling noise under load, significant power loss
  1,750–5,000 $

+ 9 more engine weaknesses + vehicle weaknesses

Single twin-scroll turbo instead of the N54's twin-turbo — torque comes in evenly from 1,200 rpm and doesn't let up to 5,500. At idle a deep, barely audible hum; under load a rich rumble that surpasses the N54 in refinement but lacks its rawness. Above 5,000 rpm the turbo drowns out the engine — those seeking naturally-aspirated emotion will be disappointed. Valvetronic almost completely eliminates the throttle butterfly; throttle response is therefore more direct than on most turbo engines. The electric water pump is the Achilles heel: fails between 80,000 and 120,000 km without warning. Valve cover gasket starts leaking from 100,000 km — replace the entire cover, not just the gasket. Oil changes every 10,000 km instead of BMW Longlife, 5W-30 LL-04. Tuning: Stage 1 brings 350+ hp; from Stage 2 the HPFP becomes the bottleneck — fit the B58 pump. Considered one of the most reliable M-engines of the last 20 years when maintained properly.

• !! Bearing wear from neglected maintenance from 120,000 km

  Connecting rod bearings wear with extended oil change intervals or oil starvation. Particularly affects vehicles on Longlife intervals driven hard.

  Symptoms: Knocking from the engine block, oil pressure warning, metallic particles in the oil
  1,500–5,000 $
  Ad BMW N55 connecting rod bearingBMW N55 Lagerschalen
• !! Electric water pump failure from 130,000 km

  The N55 electric water pump typically fails between 100,000 and 150,000 km. A sudden failure while driving can cause overheating damage to the cylinder head or gasket within minutes.

  Symptoms: Overheating warning; cooling fan runs continuously or intermittently; slow warm-up; coolant loss at idle
  700–1,500 $
  Ad BMW N55 water pump elektrischBMW N55 thermostatElektrische water pump 11517632426
• !! Valvetronic eccentric shaft wear from 150,000 km

  Oil jet for eccentric shaft lubrication clogs with poor oil maintenance. Shaft wears excessively — loud ticking and Valvetronic system failure.

  Symptoms: Ticking noise from engine bay, rough idle, misfires, power loss, extended cranking on start
  800–2,500 $
  Ad eccentric shaft N55B30Valvetronic actuator N55

+ 10 more engine weaknesses + vehicle weaknesses

4.0-litre V8, 420 hp, 8,300 rpm rev limit — eight individual throttle bodies, cross-plane crankshaft. Below 5,000 rpm a deep V8 grumble; from 7,500 rpm the note tips into the hysterical; at 8,000+ the cockpit vibrates noticeably — no isolation left between driver and machinery, and that is exactly the point. Con rod bearing shells are the fear issue: factory tolerances too tight (0.001" instead of 0.0025"), catastrophic failure on cold-start abuse. Preventive replacement with aftermarket bearings every 60,000–80,000 km; oil analysis before every purchase is mandatory. Throttle body actuators with plastic gears fail from 80,000 km — limp mode. Warm-up below 3,000 rpm is not a tip but a survival strategy. Last V8 M3, last M3 coupé, last naturally aspirated M3 — three last times in one car.

• !! Connecting rod bearings — clearance too tight from factory from 90,000 km

  Factory bearing clearance of 0.025 mm instead of the recommended 0.063 mm. Under heat and high revs the bearing shells wear prematurely. Metal particles contaminate the entire oil system. Preventive replacement with ACL bearing shells and ARP bolts by 100,000 km at the latest.

  Symptoms: Knocking from the engine block on a warm engine, dropping oil pressure at high revs, metal particles in the oil filter. In the final stage: sudden engine seizure.
  2,500–5,500 $
  Ad connecting rod bearing S65B40ACL Race Series Lagerschalen S65ARP connecting rodschrauben S65 BMW M311247840903 connecting rod bearing BMW E92 M3
• !! Throttle body actuators — plastic gears break from 120,000 km

  All eight individual throttle bodies have electric actuator motors with plastic gears that inevitably break. From around 120,000 km, bank 2 typically fails first. Replace both banks at the same time; grease the linkage every 3 years. Fault codes 2B15/2B16.

  Symptoms: Sudden power loss, limp mode active, DSC and EML lights on, engine runs rough after about 5 minutes of driving. Affects 100% of S65 engines at the relevant mileage.
  500–1,800 $
  Ad throttle bodynstellmotor S65B40Throttle Actuator E92 M3 Bank 1 Bank 213627834494 throttle body BMW M3actuator motor Zahnrad S65
• !! VANOS hub covers — plastic breaks and blocks oil strainer from 120,000 km

  The four VANOS hubs have plastic covers that become brittle and break with age. Fragments fall into the sump and can block the oil pick-up strainer — oil starvation and engine damage. Aluminium replacement covers (Evolve, MMX) are the permanent solution.

  Symptoms: No warning — in the worst case sudden oil pressure loss and engine damage. Check preventively during connecting rod bearing service.
  200–600 $
  Ad VANOS Hub Cover S65 AluminiumEvolve VANOS Deckel E92 M3MMX VANOS Cover S65B40VANOS camshaftnabdeckung S65

+ 7 more engine weaknesses + vehicle weaknesses