1998-2005 · 1.9L M43 / 2.0L N42/N46 4-cylinder petrol
The E46 generation is beloved for its driving dynamics and classic styling, making it popular with enthusiasts and first-time BMW buyers. The 318i is the entry-level model with adequate performance for daily driving. Pre-facelift (1998-2001) uses the simpler M43 engine with timing chain and no Valvetronic - more reliable but less powerful. Facelift models (2001-2005) have the N42/N46 engine with Valvetronic and more power, but suffer from timing chain tensioner failures, Valvetronic system issues, and higher oil consumption. Main concerns across all variants: cooling system (expansion tank brittle plastic), rear subframe cracking (especially pre-2002), window regulators, control arm bushings, and CCV valve failures causing oil leaks. Parts are widely available and reasonably priced. Maintenance history is critical - well-maintained examples can exceed 250,000 km.
Cooling system expansion tank failure€100 - €1,400
Brittle plastic cracks after 75,000-100,000 km, can cause catastrophic overheating · more· less
The plastic expansion tank becomes brittle after heat cycles and cracks, leaking coolant. This is the most common first failure in E46 cooling systems, typically occurring at 75,000-100,000 km intervals. If ignored, coolant loss leads to overheating, which can warp the aluminum head in seconds, requiring a €2,000-2,500 top-end rebuild. The tank itself costs €85-95, but shops often recommend replacing the entire cooling system (hoses, radiator, thermostat, sensor) at once, costing €950-1,400 total. BMW's inline-six is particularly vulnerable to heat damage due to the long aluminum head design.
Tensioner loses pressure overnight causing cold start rattle at 60,000-100,000 km · more· less
The N42/N46 engines (facelift 2001-2005 models) have a notorious timing chain tensioner design flaw. The tensioner has a release valve that weakens over time, allowing oil pressure to bleed off overnight. This causes a distinctive rattle for 1-30 seconds on cold start. If the rattle lasts more than a few seconds, the chain has stretched and the chain, guides, tensioner, and sprockets all need replacing. Tensioner alone costs €25-50, but full timing chain kit replacement runs €400-1,800 including labor due to front-end disassembly required. The M43 engine (pre-facelift 1998-2001) doesn't have this issue. Ignoring the rattle can lead to chain skip and catastrophic valve-to-piston contact.
Rear subframe cracking€1,200 - €2,500
Metal fatigue causes cracks at subframe mounting points, more common pre-2002 · more· less
All E46 models are prone to cracking at and around the rear subframe mounts. Technically, it's not the subframe itself that cracks but the Rear Axle Carrier Panel (RACP) section of the unibody chassis where the subframe attaches. This is caused by inadequate reinforcement in the mounting area combined with stress from driving, especially spirited driving or track use. Most prevalent in 1999-2002 models, though allegedly rectified around 2002. Symptoms include clunking/creaking noises from the rear, misaligned suspension, and uneven tire wear. Repair typically costs €1,200-2,500 depending on damage extent. Some owners have had mobile welders repair small cracks for as little as €550. During repair, it's recommended to replace differential bushings, subframe bushings, and trailing arm bushings.
Valvetronic system failure (N42/N46 engines)€125 - €3,000
Eccentric shaft, sensor, or motor failures after 100,000-150,000 km cause limp mode · more· less
The N42/N46 engines use BMW's Valvetronic system for variable valve lift. Common failures include broken Valvetronic return springs (notorious), eccentric shaft sensor failure, and Valvetronic motor failure when hot. Symptoms include rough idle, limp mode, reduced power, and error codes (P1083, P1084, P1347, P1348). Budget fix: used VVT ECU for €125-200. Eccentric shaft replacement alone costs €800+ for parts, excluding labor. Full dealer repair including motor, shaft, and ECU can reach €3,000. The M43 engine doesn't have Valvetronic and avoids these issues entirely. Special BMW tooling and scan tool are required for proper repair and limit stop relearning.
Window regulator failure€80 - €750
Plastic clips become brittle and snap, very common on aging E46s · more· less
Window regulators are notoriously prone to failure on E46s. The plastic components become brittle from heat/cold cycles and snap, especially if windows are used frequently. Usually it's just the clip that breaks while the linkage and pulley are reusable. DIY repair kits cost €10-20. Complete aftermarket regulators cost €80-110, while OEM parts run €150 each. Dealer installation quotes range from €350-750 per window. Independent shops charge €230-575. Front regulators take longer to replace than rears. Expect to replace 2-3 regulators over the life of a high-mileage E46.
Valve gets stuck causing vacuum leaks, oil leaks, rough idle at 70,000-120,000 km · more· less
The CCV valve and its 4 associated hoses fail between 70,000-120,000 km, typically around 80,000-90,000 km. When the valve gets stuck open, it causes a vacuum leak leading to rough idle, increased oil consumption, oil leaks through seals/gaskets, white smoke from exhaust (oil burning in combustion chamber), and potential Check Engine light. Many owners mistake CCV failure for valve stem seal problems. Simple DIY diagnosis: place a plastic bag over the oil fill hole at warm idle - if it gets significantly sucked in, the valve is stuck and bad. Parts cost €50-150 (valve, filter, hoses), labor about 1-2 hours at €100-150/hour. Total repair: €150-450. BMW recommends replacing the valve filter every 60,000 km.
Control arm bushings wear€200 - €1,300
Lower control arm bushings fail after 80,000-130,000 km causing clunking sounds · more· less
Lower control arm bushings typically last 60,000-90,000 km before wearing out, though potholes, salt, and aggressive driving accelerate failure. Symptoms include rattling or clunking from the front over small bumps or gravel roads, and noticeable play in the steering as it worsens. Bushing sets cost €6-95 depending on quality (Meyle HD, Lemfoerder, Powerflex). Complete control arms with bushings: under €400 for OEM parts. Dealer quotes: €582-1,300. Independent shops: €200-1,075 including alignment. DIY labor: some owners paid enthusiasts €180 for installation. Add €90-160 for wheel alignment after replacement.
Ignition coil failure€50 - €1,680
Bremi coils fail causing misfires, rough idle, power loss after 140,000 km · more· less
Ignition coils typically last upward of 140,000 km. Symptoms include engine misfiring, rough idle with heavy vibration, sluggish acceleration or "bogging down" effect, decreased fuel efficiency from incomplete combustion, and Check Engine light. BMW service bulletin states that for E46 built 9/02-10/04, if any Bremi coil is defective, all six should be replaced with Bosch parts - Bremi coils are notorious for failures. Single coil replacement: €191-274. Full set of 6 coils: €344 online, but dealer quotes reach €1,680 including labor. DIY replacement takes under 2 hours. Failed coils can damage the catalytic converter if ignored due to unburned fuel.
Water pump and thermostat failure€600 - €1,200
Classic E46 issue typically occurring at 70,000-100,000 km · more· less
Water pump and thermostat failures are common E46 issues. Symptoms include coolant warning light, engine overheating, or poor cabin heating. The thermostat alone costs €65-110 (Mahle vs BMW), while a genuine BMW pump is over €500 (Pierburg aftermarket around €300). Labor-intensive job requiring patience and strength. Shops typically charge €600-1,200 total including the U-shaped connecting hose (€20-50), coolant, and labor. One owner paid close to €1,000 including pump, thermostat, u-hose, reservoir, cap, and labor. It's recommended to replace both pump and thermostat together, and inspect the entire cooling system during the job. Failed water pumps can be caused by bad thermostat, radiator, or head gasket issues.
Fuel pump failure€150 - €1,000
High-pitched whine, long cranking times, hesitation under load · more· less
Fuel pump failure symptoms include long cranking before starting, engine hesitation especially uphill, high-pitched whine or buzzing from rear seats, sudden stalling at idle, rough idling and misfires, and difficulty starting when warm. Later models (post-2001) have a separate fuel pump control module (EKP) under the rear seat that can fail and mimic pump failure symptoms - connector pins prone to overheating/melting. Diagnostic: test fuel pressure at the Schrader valve on fuel rail (spec: 50-55 PSI key-on/engine-off). DIY replacement: €150-400 for quality parts (Bosch, VDO, Genuine BMW) plus fuel filter. Professional: €650-1,000 including labor. Avoid cheap €40-80 eBay pumps - they fail prematurely.
Reliable if maintained, but aging components add up
The E46 318i is reasonably reliable for a 20+ year old BMW, especially the simpler M43 engine (pre-facelift). The N42/N46 engines in facelift models offer more power but introduce Valvetronic complexity and timing chain issues. Most problems are well-documented with established fixes, and parts are widely available at reasonable prices. The key is maintenance history - well-maintained examples with complete service records can exceed 250,000 km, while neglected ones become expensive projects. Budget for the inevitable cooling system refresh, and be prepared for timing chain work on N42/N46 engines.
Pre-Purchase Inspection Checklist
General checks
Service history
Complete service records are essential. Verify oil changes at proper intervals (15,000 km max for N42/N46, ideally more frequent). Check for cooling system work, timing chain replacement on facelift models.
Tires
Check tread depth, age (date codes), and uneven wear patterns indicating suspension issues. Standard sizes: 195/65 R15 or 205/55 R16.
Cold start
Must start engine completely cold. Listen carefully for timing chain rattle in first 30 seconds (N42/N46 engines). Any rattle lasting more than 1-2 seconds is concerning.
Body condition
Check for rust especially on jack points, rear wheel arches, and front subframe. Look for accident damage and paint mismatch.
Test drive
Minimum 20 minutes including highway speeds. Listen for suspension noises, feel for steering play, test all gears thoroughly.
Specific for this vehicle
Check expansion tank for cracks
Inspect the plastic expansion tank carefully for any hairline cracks or signs of leakage. Press gently on the tank - if it feels brittle or cracks easily, replacement is imminent. This is the most critical check.
Listen for cold start timing chain rattle (N42/N46)
On facelift 2001-2005 models, start the engine completely cold and listen for rattle in the first 30 seconds. Brief rattle (1-2 seconds) is acceptable; longer rattle indicates stretched chain needing replacement.
Inspect rear subframe mounting points
Look underneath at the rear subframe mounting areas for visible cracks or separation. Most critical on pre-2002 models. Clunking noises from the rear during test drive are a red flag.
Test all four windows
Operate each window fully up and down several times. Slow operation, clicking sounds, or windows that stick indicate imminent regulator failure.
Check for oil leaks
Inspect valve cover gasket, oil filter housing gasket, and around the CCV valve for oil seepage. Look under the car for any drips. Check oil level - excessive consumption indicates CCV or valve stem seal issues.
CCV system diagnosis (if high oil consumption)
If the seller reports high oil consumption, perform the plastic bag test over oil fill hole at warm idle. Bag getting sucked in significantly = bad CCV valve.
Test drive for control arm wear
Drive over speed bumps and rough roads. Listen for clunking or rattling from front suspension. Check for steering play or wandering at highway speeds.
Check for smooth idle and power delivery
Engine should idle smoothly without misfires. Acceleration should be smooth without hesitation. Rough running can indicate ignition coil, Valvetronic, or fuel system issues.
Verify engine variant
Determine if it's M43 (pre-facelift, more reliable) or N42/N46 (facelift, more powerful but more issues). This affects risk assessment and budget planning.
Recalls and Technical Service Bulletins
Various recalls may apply depending on production dateCheck by VIN
Bremi ignition coil replacement TSB (9/02-10/04)Replace all 6 with Bosch
Contact a BMW dealer or visit bmwusa.com/safety-and-emission-recalls.html with your VIN to verify all recalls have been completed. Check NHTSA.gov for additional TSB information. The E46 has numerous model-year-specific TSBs covering various systems.
Warranty Status
Factory warranty (2 years)Expired on all E46s
Extended warrantyAvailable from third parties
All E46 318i models are long outside their original factory warranty period. Some independent warranty companies offer coverage for older BMWs, but read the fine print carefully - many exclude common E46 issues like cooling system components, subframe work, and wear items. Budget for repairs out-of-pocket.
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.