One of BMW's most reliable modern 3 Series, particularly the 2005-2007 N52 engine models. Popular enthusiast choice with hydraulic steering and naturally aspirated smoothness. Main concerns: oil leaks from valve cover and filter housing gaskets (very common after 80,000 km), water pump failure, and injector issues on later N53 engines (2007+). Early N52 models are significantly more reliable. No major timing chain issues unlike smaller TSI engines. Avoid N53 without warranty due to expensive injector failures.
Expected Annual Maintenance Costs
€850 - €1,600/year
15,000 km/year
Fixed costs
€550-900
Risk buffer
€300-700
What Can Break
bars = likelihood
Oil filter housing gasket leak€400 - €1,000
Extremely common on all E90 N52/N53 engines, typically appears 80,000-120,000 km · more· less
The oil filter housing sits on top of the engine above the serpentine belt. When the gasket fails, oil leaks onto the belt causing premature wear and potential belt slippage. If severe, the belt can get sucked through the front crank seal into the crankcase, causing catastrophic damage. BMW dealers charge €800-1,000, independent shops €400-600. DIY cost is only €25-65 for gasket kit and can be done in under an hour without removing intake manifold despite what BMW manual says. Many owners also replace the plastic coolant flange below at the same time (€50-100 extra) as it becomes brittle from oil contamination.
Valve cover gasket oil leak€400 - €1,400
Very common, gasket becomes brittle with heat/age, leaks appear from 60,000 km · more· less
Valve cover gasket leaks are frequent on N52/N53 engines. Over time the gasket cracks due to heat cycles. If only the gasket needs replacing, expect €400-650 at independent shops (BMW dealers charge €650-920). However, if the valve cover itself is cracked or warped (common on early magnesium covers), full replacement costs €1,200-1,400+. Dealers charge over 8 hours labor though actual time is less. Check if your car has magnesium (aluminum screws) or plastic (steel screws) valve cover - magnesium versions are more prone to warping.
Water pump failure€600 - €1,200
Electric pump made of plastic, typically fails 70,000-130,000 km · more· less
BMW's electric water pump is a known weak point. The plastic housing cracks and corrodes over time, leading to coolant leaks and overheating. Failure typically occurs around 80,000-120,000 km. OEM BMW pump costs €400-500, aftermarket Pierburg €250-350. Always replace thermostat simultaneously (Mahle €65, BMW €110) plus the U-shaped connector hose. Total dealer cost exceeds €1,000, independent shops €600-800. Labor is 3-4 hours due to tight engine bay. DIY is challenging but doable. Failure can destroy the engine if overheating isn't caught immediately.
Very common on N53 direct injection engines, often fail by 80,000 km · more· less
The N53 engine (2007-2013 in EU market 330i) is notorious for injector failures. Symptoms include rough cold start, lumpy idle, and "bag of nails" rattling. One local mechanic reports fitting new N53 injectors weekly. Failed injectors often cascade - when one fails, others follow quickly. You must replace all 6 injectors (€1,400-2,200) and often the NOx sensor too (add €200-400). Only Index 11 injectors work reliably. Remanufactured sets cost €600-800 from German suppliers. This is THE reason to avoid N53 without warranty. Early N52 engines (2005-2007) don't have this issue.
Window regulator failure€200 - €750
Well-known E90 problem, cable detaches from pulley system · more· less
Window regulators failing is a "well known problem" on E90s. The internal cable comes detached from the pulley system. Some owners report having all 4 window regulators replaced before the 4-year warranty expired. Symptoms: window won't roll up or falls off track. BMW dealers sometimes fix under goodwill but typically charge €600-750 per window. Independent shops €200-350. DIY repair takes about 1 hour per window, parts cost €100-150. Important: inspect window guide and seal when replacing - worn seals increase friction and cause premature regulator failure again.
DISA valve failure (N52 engines)€200 - €600
Intake manifold flaps fail 100,000-150,000 km, can cause engine damage · more· less
N52 engines have two DISA (variable intake) valves that adjust airflow at different RPMs. The flaps can fail to seal properly or the metal pin can break off. If the pin falls into the engine, catastrophic damage occurs. Typical failure is 100,000-150,000 km. Symptoms: rattling noise, lack of low-end power, check engine light with codes P1083/P1084/P1347/P1348, or mysterious humming felt in accelerator pedal. E90 DISA units are sealed and cost €200+ each. The exterior valve is easy to access, but interior valve requires removing intake manifold (€400-600 labor). Always replace both together. Preventive replacement at 100,000 km recommended.
VANOS solenoid failure€150 - €600
Oil sludge clogs solenoids, typically 100,000-150,000 km if long service intervals used · more· less
Variable valve timing (VANOS) solenoids get contaminated with oil sludge, especially if BMW's long service intervals (15,000+ km) are followed. Symptoms: sluggish acceleration, rough idle, loss of power, limp mode, check engine light. Two solenoids cost about €100 each. Replacement takes only 20 minutes and is DIY-friendly. Some solenoids can be cleaned rather than replaced. Independent shop labor €100-200, dealers charge more. Use quality solenoids: Febi (best value) or Pierburg (premium), avoid cheap URO brand. Frequent oil changes (every 8,000-10,000 km) prevent this issue.
Ignition coil failure€150 - €700
Common failure on BMWs, usually one coil at a time after 100,000 km · more· less
Ignition coils are extremely common failure parts on E90s. Symptoms: misfire code and check engine light. Coils typically last 140,000+ km but some fail earlier. When one fails, others often follow within months. Parts are cheap: OEM Bosch €30-80 each, aftermarket €20-40. BMW dealers charge €700 for full replacement, independent shops €200-400. DIY replacement takes under 2 hours with just an 8mm socket and 5mm hex bit. Earlier cars (before 03/2006) have different coils so check production date. Replace with latest Bosch revision. While annoying, this is a minor issue compared to other E90 problems.
System clogs, causes rough idle and oil consumption, usually after 100,000 km · more· less
The PCV valve and hoses can clog or fail, causing rough idling, oil leaks, increased oil consumption, and whistling noise from engine bay. Simple PCV valve replacement costs €150-350. However, some E90 models have the PCV valve integrated into the plastic valve cover, requiring full valve cover replacement (€1,200-1,400). Filter should be replaced every 60,000 km. Symptoms overlap with VANOS issues. A clogged system restricts ventilation, building crankcase pressure that forces oil past gaskets. Regular maintenance prevents this, but it's often neglected until symptoms appear.
Control arm bushings wear€350 - €1,000
Front suspension bushings wear by 120,000-150,000 km, rear slightly later · more· less
Control arm bushings are wear items that deteriorate over time. E90 front suspension is reliable overall but bushings need replacement by 120,000-150,000 km. Symptoms: clunking over bumps, vague steering, uneven tire wear. Professional replacement costs €665-1,030. Many owners replace complete control arms with bushings pre-installed (€330 for upgraded M3-style kit) rather than pressing bushings (requires hydraulic press). Front dampers also wear by 150,000+ km. Sway bar bushings are cheaper and easier. Overall E90 suspension longevity is much better than older E46 generation.
Alloy wheel cracks (if run-flat tires)€200 - €600
Hairline cracks develop on 18-19" wheels with run-flat tires, especially rear wheels · more· less
E90s with original 18-19" alloys and run-flat tires are prone to hairline cracks, particularly rear wheels due to negative camber. The problem affects Styling 225 (MV4) wheels most severely - even featured on BBC Watchdog. Run-flats have extremely stiff sidewalls that don't absorb impacts, transferring all force to the rim. Speed bumps and potholes cause gradual cracking. BMW claimed all cases showed impact damage, but many owners dispute this. Solution: switch to conventional tires (adds cushioning) or downsize wheels. Check all wheels carefully for cracks during inspection. Welding is possible but replacement is safer (€200-600 per wheel depending on style).
Reliable for a BMW, but gasket leaks are almost guaranteed
The E90 330i with N52 engine (2005-2007) is one of BMW's most reliable modern cars and highly regarded by enthusiasts. However, oil leaks from valve cover and filter housing gaskets are virtually certain by 100,000 km - budget for this. Water pumps also fail predictably. The N53 engine (2007-2013) is less reliable due to injector issues and should be avoided without warranty. Regular oil changes (8,000-10,000 km) and addressing leaks promptly prevent most major problems. With proper maintenance, N52 engines easily exceed 300,000 km.
Pre-Purchase Inspection Checklist
General checks
Service history
Complete BMW dealer or specialist service records essential. Verify oil changes at proper intervals (ideally 8,000-10,000 km, not BMW's 15,000+ km).
Tires
Check tread depth, age (date codes), uneven wear. Consider switching from run-flats to conventional tires for better ride and wheel protection.
Cold start
Must start engine completely cold. Listen for unusual rattles, especially first 30 seconds after start.
Body condition
Check for rust, accident damage, paint mismatch. E90s are often victims of odometer fraud - verify mileage against service records.
Test drive
Minimum 20 minutes including varied speeds. Listen for suspension noises over bumps.
Specific for this vehicle
Check for oil leaks - critically important
Inspect oil filter housing (top of engine) and valve cover for leaks. Look underneath engine for oil residue on serpentine belt area. Small leaks will become major problems. Ask seller about any oil leak repairs already done.
Verify engine type: N52 (2005-2007) or N53 (2007-2013)
Check production date and verify which engine. N52 is significantly more reliable. N53 should have proof of Index 11 injectors or assume €1,500-2,000 injector replacement needed soon.
Listen for DISA valve rattle or humming
During test drive, listen for rattling from intake manifold or mysterious humming felt through accelerator pedal. Check for lack of low-end power.
Test all four windows thoroughly
Roll each window up and down multiple times. Listen for grinding, check they don't fall off track. Window regulator failure is extremely common.
Check coolant level and inspect water pump area
Low coolant or visible leaks near water pump indicate imminent failure. Ask when water pump was last replaced. If original pump with 80,000+ km, budget for replacement.
Inspect all 4 alloy wheels for hairline cracks
Carefully examine wheels, especially rear wheels if car has 18-19" wheels with run-flats. Look for cracks radiating from bolt holes or spoke areas. Use flashlight.
Check for VANOS codes and performance
If seller allows, scan for fault codes. Look for P1083/P1084/P1347/P1348 (DISA) or VANOS-related codes. Test acceleration feels strong throughout rev range.
Verify VANOS recall completed (if applicable)
N52K/N52T engines built Sept 2009-Nov 2011 have VANOS gear bolt recall (14V-176). Verify completion with BMW using VIN.
Inspect plastic coolant flange below oil filter housing
Look at plastic coolant flange - if oil-soaked or showing cracks, it will fail soon (€50-100 part but indicates oil leak from filter housing above).
206 Technical Service Bulletins on fileReview with mechanic
Contact BMW with the 17-digit VIN to verify all recalls completed. The VANOS recall only affects specific N52K/N52T engines from 2009-2011. E90Post forum maintains complete TSB list for this generation.
Warranty Status
Factory warranty (3 years)Expired on all E90s
Extended warranty availabilityAvailable from third parties
All E90 330i models are outside their original factory warranty. Extended warranties are available from third-party providers - highly recommended for N53 engine models due to expensive injector failures. N52 models are reliable enough that warranty may not be cost-effective unless high mileage.
This report is for informational purposes only and does not constitute professional advice. Estimates may be inaccurate. Always have a qualified specialist inspect the vehicle before purchase. We accept no liability for decisions made based on this information.