1998-2005 · M52TU/M54 inline-6 petrol (150-170 hp)
A beloved classic among BMW enthusiasts, praised for its balanced handling, smooth inline-six engine, and relative simplicity compared to modern BMWs. Mechanically robust when maintained, with engines easily exceeding 200,000 km. However, requires diligent preventive maintenance - the plastic cooling system components, VANOS seals, and rear subframe mounting points are well-documented weak spots. Not for budget-conscious buyers who skip maintenance, but rewards those who stay on top of it with reliable, engaging driving dynamics. Parts are widely available and many repairs are DIY-friendly.
Expected Annual Maintenance Costs
€850 - €1,500/year
15,000 km/year
Fixed costs
€500-800
Risk buffer
€350-700
What Can Break
bars = likelihood
Cooling system failures (expansion tank, water pump)€350 - €800
Plastic components crack between 60,000-100,000 km causing overheating · more· less
The E46's cooling system is its Achilles heel. The expansion tank develops hairline cracks typically between 60,000-95,000 km due to heat cycling, and can even explode under high pressure. The water pump's plastic impeller breaks between 60,000-100,000 km, sending fragments into the system. Radiator end tanks are also plastic and prone to leaking. The thermostat housing can crack too. Complete cooling system refresh (expansion tank, water pump, thermostat, hoses) should be done preventively every 75,000-90,000 km. If the engine overheats due to cooling failure, you risk catastrophic head gasket or engine damage. Never ignore the coolant warning light - pull over immediately.
VANOS seal deterioration€250 - €900
Double VANOS seals fail, causing rough idle and loss of low-end torque · more· less
All 320i models with M52TU and M54 engines have dual VANOS (variable valve timing). The seals harden and fail over time, causing noticeably low torque below 3,000 RPM, uneven power delivery, rough idle, and increased fuel consumption. Engine surges at 3,500+ RPM. DIY seal replacement kits (Beisan Systems) cost €50-60 plus gaskets. Professional replacement costs €450-900 including valve cover gasket replacement. Some shops may recommend replacing the entire VANOS unit (€250-500 rebuilt). This is a common issue but well-documented and fixable.
Rear subframe mounting point cracking€1,200 - €4,500
Floor pan tears at subframe mounts, especially on salt-exposed cars · more· less
This is the most serious E46 structural issue. The rear subframe mounting points in the floor pan can crack or tear, especially on cars driven in winter salt conditions. Symptoms include loud clunks from the rear over bumps. BMW had a class action lawsuit over this and offered reimbursement. Their initial foam injection "fix" was ineffective. Proper repair requires welding reinforcement plates (€1,200-2,500 at specialists) or cutting out the damaged section and replacing it (€4,000-6,000 at dealers). Many E46s already have this repair done. Essential to check during pre-purchase inspection, though minor cracks are only visible with subframe dropped.
Lower control arm bushing wear€400 - €1,000
Rubber bushings fail after 80,000-130,000 km causing vague steering · more· less
Front lower control arm bushings are a notorious E46 weak point. OEM rubber bushings deteriorate, causing rattling/clunking over bumps, vague steering, and wandering on uneven roads or in wind. Ball joints are welded to the arms, so entire arms must be replaced (can't just replace bushings). Aftermarket Meyle HD arms with solid steel bushings (€150-200 for parts) are more durable than OEM. Labor is 3-4 hours including alignment. Typical failure occurs between 80,000-130,000 km but can happen earlier with rough roads or salt exposure.
Window regulator failure€80 - €400
Plastic clips and cables break, window drops or won't move · more· less
E46 window regulators are a common failure item due to brittle plastics and delicate components. Heat and cold cycles make clips snap. Symptoms: window drops into door, won't go up/down, or slow operation. Aftermarket regulators (€80-150) often fail quickly. OEM BMW parts (€150-200 each) are more reliable. DIY replacement takes 1-2 hours. Dealer installation costs €350-750. Often 2-3 regulators need replacement over the car's life. Front regulators fail more frequently than rear.
Gaskets harden from heat cycles, oil seeps onto engine block · more· less
Oil leaks are extremely common on E46s. The valve cover gasket (€50-100 parts, €300-600 with labor) typically leaks after 100,000 km. The oil filter housing gasket (€5-10 parts, €150-400 labor) is located on top of the engine and hardens from heat, leaking oil down the front of the block. The PCV/CCV system can also cause leaks. While the leaks start small, they worsen over time. Regular inspection is essential - low oil levels from unnoticed leaks can cause engine damage. DIY gasket replacement is straightforward and saves significant money.
DISA valve failure€120 - €350
Intake manifold flap breaks at 75,000-100,000 km causing rattle · more· less
The DISA (variable intake manifold) valve uses a plastic flap held by a metal pin. Heat and age cause the plastic to crack or the pin to break loose. Symptoms: loud rattling from intake, rough idle, lean codes, loss of low/mid RPM power. If the pin or plastic enters the engine, catastrophic damage occurs. M52TU engines are easier to repair (individual components), but M54 engines typically need full DISA replacement (€120-200 for aftermarket, €350+ for OEM). Repair kits exist (€50-75). Listen carefully for rattling during inspection - this is critical to catch early.
PCV/CCV system clogging€100 - €500
Crankcase ventilation clogs, causing oil leaks and rough idle · more· less
The PCV (Positive Crankcase Ventilation) system recirculates crankcase gases. The valve and hoses clog over time, causing excessive crankcase pressure. This leads to oil weeping from timing cover, oil pan, and valve cover seals. Symptoms: rough idle, oil consumption, visible oil leaks. Replacement kits cost €50-150 DIY or €450-500 installed. The valve cover can crack from pressure (plastic construction). Book time is 4 hours but experienced mechanics can do it in 1.5-2 hours. Some owners install catch-can bypasses for under €50.
Rear coil spring failure€150 - €450
Springs snap at bottom coil from rust, more common in wet/salt climates · more· less
E46 rear coil springs commonly snap at the last two lower turns. Poor drainage in the spring perch allows water and debris to pool, causing rust and fracture. More prevalent in UK/Netherlands due to salted roads. Symptoms: clunking from rear, uneven ride height. Springs cost €80-200 each (OEM BMW €140+). Must replace in pairs. DIY takes about 1 hour per side with basic tools. Shops charge €150-450 for the job. Some owners report failures as early as 40,000 km, others at 80,000+ km. Aftermarket heavy-duty springs (Suplex) offer better corrosion resistance.
Power steering pump/reservoir leaks€200 - €600
Hoses crack, reservoir filter clogs, pump fails from running dry · more· less
The E46's power steering system uses LF-20 pumps known to fail. Common leak points: low-pressure hoses near PS cooler, two hoses under reservoir (supply and return lines), and reservoir connections. The reservoir has a non-serviceable filter that clogs, making the pump work harder. Symptoms: stiff steering (especially at low speed), whining/groaning when turning, fluid leaks, foamy fluid, burning smell. Check fluid type - E46s use either CHF11S or ATF Dexron III (not interchangeable). Flush every 2-3 years. Replace reservoir if cracked/bulging and any leaking hoses.
Alternator failure€300 - €700
Original alternators reaching end of life on 20+ year old cars · more· less
Many E46s still run original factory alternators, now 20+ years old. Symptoms: battery warning light, dim lights while running, battery won't hold charge, grinding/whining noises. Test: running engine should show 13.5-14.5V; if below 12V, alternator is failing. Alternators cost €125-380 (aftermarket €125, Bosch reman €190, OEM €270+). Rebuild kits with bearing/bushing/regulator cost €35-40. Labor is 2-3 hours due to modular front end requiring cooling fan removal. Total shop cost: €500-700. DIY saves money but requires patience.
Mechanically solid but requires preventive maintenance
The M52TU and M54 inline-six engines are famously robust and can easily exceed 200,000 km with proper care. However, the E46 has several well-documented wear items that must be addressed proactively: cooling system refresh every 75,000-90,000 km is essential, VANOS seals should be replaced when symptoms appear, and the rear subframe must be inspected for cracks. Parts are widely available and relatively affordable. Many repairs are DIY-friendly for mechanically inclined owners, significantly reducing costs. Budget for regular maintenance and you'll have a reliable, enjoyable classic BMW.
Pre-Purchase Inspection Checklist
General checks
Professional pre-purchase inspection
Strongly recommended - find a BMW specialist shop. Typical PPI costs €100-200 but can save thousands.
Service history
Complete service records essential. Verify regular oil changes, cooling system refresh, VANOS work if done.
Tires
Check tread depth (minimum 3mm), age (date codes - replace if 6+ years old), uneven wear indicating suspension issues.
Cold start
Must start engine completely cold. Listen for timing chain rattle (rare but serious), VANOS roughness, lifter noise.
Test drive
Minimum 20 minutes including highway speeds. Test all gears (manual) or smooth shifts (automatic). Check steering response.
Specific for this vehicle
Inspect rear subframe mounting points
Critical - look underneath for cracks in floor pan around subframe mounts. Listen for clunks over bumps. Complete inspection requires dropping subframe.
Check cooling system thoroughly
Inspect expansion tank for cracks (use flashlight), radiator for leaks at corners, hoses for softness/cracks. Check coolant level and condition (should be clean, not brown/rusty).
Test for VANOS seal wear
From cold start, note whether engine has low torque and hesitation below 3,000 RPM, then surges above 3,500 RPM. Rough idle is another indicator.
Listen for DISA valve rattle
Start engine and listen carefully for rattling from intake manifold area. This is critical - broken DISA parts can destroy the engine.
Check for oil leaks
Inspect valve cover perimeter, front of engine block (oil filter housing), and underneath for drips. Check oil level - M54 uses some oil normally but excessive consumption indicates problems.
Test window regulators
Operate all four windows multiple times. Listen for unusual noises, slow operation, or hesitation.
Inspect suspension and steering
Drive over small bumps and rough roads - listen for clunking (control arms, springs). Check for vague steering or wandering (bushings). Test power steering at low speed for whining.
Verify electrical systems
Test all features: lights, climate control, sunroof, mirrors, seats. Check for airbag warning lights, DSC operation. Inspect instrument cluster for pixel fade.
Look for rust in wheel arches and sills
Check rear wheel arches and sills, especially behind plastic trim. E46s rust in these areas, particularly in wet climates.
Check rear springs for breakage
Look at rear springs through wheel wells - bottom coil sometimes snaps off but remains seated. Uneven ride height is a clue.
Recalls and Technical Service Bulletins
Rear subframe mounting point cracking (1999-2006)Class action settlement - check if repaired
Fuel injection system deposits (M54 engine)TSB SI B 13 01 07
Steering pinion shaft squeaking noiseTSB SI B 32 07 08
Passenger airbag (certain batches)Check with BMW dealer using VIN
Contact BMW with VIN to verify all recalls and TSBs have been addressed. The rear subframe issue is particularly important - many E46s have already had reinforcement work done under the class action settlement.
Warranty Status
Factory warranty (3 years / 100,000 km)Expired on all E46 models
Extended warranty optionsLimited availability for cars this old
All E46 320i models are 19-27 years old and well outside any factory warranty. Some independent warranty providers may offer limited coverage for low-mileage, well-maintained examples, but expect high premiums and many exclusions for wear items. Most E46 owners self-insure by maintaining an emergency repair fund and performing preventive maintenance.
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.