Popular German sedan known for comfort and fuel economy, but plagued by a notorious balance shaft/oil pump design flaw affecting roughly 1 in 3 cars between 80,000-130,000 km. The 140 hp (BPW) variant has no DPF and is generally considered more reliable than the 170 hp version, which adds injector issues. Multitronic CVT gearboxes had widespread problems before 2006 7-plate clutch upgrade. Manual gearbox versions are far more reliable. Avoid early 2005-2006 models unless balance shaft conversion has been completed.
Expected Annual Maintenance Costs
€750 - €1,600/year
15,000 km/year
Fixed costs
€400-700
Risk buffer
€350-900
What Can Break
bars = likelihood
Balance shaft / oil pump failure€800 - €5,000
Hex shaft wears down causing catastrophic oil pressure loss · more· less
This is the most critical issue with B7 2.0 TDI engines. Reports suggest 1 in 3 cars (33%) experienced severe engine problems between 2005-2009. The hexagonal balance shaft is 4mm too short and wears over time. Failure typically occurs between 80,000-130,000 km. You'll hear a rattling/failed flywheel sound as it begins to fail. Once the oil pressure light comes on, shut down immediately - continued driving will destroy the engine. Preventive replacement of modified balance shaft costs €600-900 (parts + labor at specialist). Engine replacement after failure: €3,000-5,000+. Only 5% of owners replace it preventively. Strongly recommended to verify this has been done before purchase, or budget €700-900 to have it done immediately.
Short trips prevent regeneration, causing blockage and turbo damage · more· less
Only affects 170 hp variant (BRD/BRE engines) - the 140 hp BPW engine has no DPF. The DPF requires regular highway driving at constant speed to regenerate. Short commutes (under 15 km) cause rapid clogging. Symptoms: lack of power, white smoke, warning light, eventually limp mode. Can cause turbo overwork and failure. Sometimes the issue is just a faulty pressure sensor (€100-200 fix). Cleaning costs €300-600. Full replacement: €1,200-1,800 at dealer, €600-900 aftermarket. Drive 20-30 miles at 100+ km/h monthly to prevent issues. If you only do short trips, avoid the 170 hp variant entirely.
Fuel injector failure (170 hp variant)€800 - €2,000
Early Siemens piezo injectors prone to failure, recall issued · more· less
Primarily affects the 170 hp BRD/BRE engines with piezo injectors. Early 2.0 TDI PD engines had faulty Siemens injectors - Audi issued a recall. Contact dealer with VIN to verify recall completion. Symptoms: rough running, poor starting, black smoke, reduced power. Single injector replacement: €200-400 parts + €200-300 labor. All four injectors: €800-1,200 parts + €400-600 labor (requires intake manifold removal). The 140 hp BPW variant uses conventional injectors and has fewer issues.
Dual mass flywheel failure€600 - €1,400
DMF rattles when cold, vibration on clutch pedal as it worsens · more· less
Known issue across B6 and B7 generations. DMF should make slight rattle when cold that disappears when warm. If rattle persists or you feel clutch pedal vibration, it's failing. Typically fails around 120,000-150,000 km with normal use, earlier with aggressive driving. Always replace clutch and DMF together. Budget garage using aftermarket parts (LUK/Sachs): €600-800. Dealer with OEM parts: €1,200-1,400. Some opt for single-mass flywheel conversion but this can damage the gearbox long-term.
Timing belt and water pump€600 - €1,400
Must be replaced every 80,000-100,000 km or 5-7 years · more· less
This is a scheduled maintenance item, not a failure, but critical to prevent catastrophic engine damage. This is an interference engine - if the belt snaps, pistons hit valves causing extensive damage. Service interval: 80,000-100,000 km or 5-7 years, whichever comes first. Always replace water pump, tensioner, and idler pulleys with the belt. Independent specialist: €600-900. Dealer: €1,200-1,400. Skipping this service will likely result in engine destruction. Always verify service history when buying.
Only applies to automatic variants with Multitronic CVT transmission. Audi issued complete recall on all CVT 2.5 TDI models and paid partial repairs on 1.9/2.0 TDI due to high failure rate. Pre-2006 models with 6-plate clutch typically failed between 50,000-100,000 km. Post-2006 7-plate clutch is better but still problematic. Symptoms: jerky behavior, sticking at 1,500 rpm when slowing, rolling back on hills in drive, flashing PRNDS, TCU failure. Friction plate replacement: €2,000-2,500. Full transmission: €3,500-4,500. Manual gearbox has no widespread issues - strongly recommended over Multitronic. If buying CVT, verify 7-plate upgrade and avoid 2005-early 2006 models.
EGR valve and intake manifold clogging€300 - €1,200
Common diesel issue - exhaust gases recirculating through EGR create carbon/soot buildup over time. Symptoms: rough idle, hesitation, black smoke, increased fuel consumption, power loss, check engine light with airflow codes. DIY cleaning: €15-30 for gaskets and cleaner (fairly easy job with basic tools). Professional cleaning: €150-300. EGR valve replacement: aftermarket €100-250, genuine Audi €300-500, plus €200-400 labor. Some dealers quote €750-1,200 for genuine parts + labor. Regular motorway driving helps reduce buildup. Cleaning every 80,000 km recommended.
Turbocharger failure€1,200 - €2,800
Oil seal failure or bearing wear causes blue smoke and rattling · more· less
Symptoms: blue-black smoke, rattling/scraping noise, power loss, wastegate rattle at certain RPM, high oil consumption. Can fail from DPF blockage forcing turbo to overwork. Average lifespan: 160,000-200,000 km with proper maintenance, less with aggressive driving or oil neglect. 1.9 and 2.0 TDI are known for snapped turbine shafts. New OEM turbo: €1,200-2,400. Dealer replacement: €2,000-2,800. Aftermarket/remanufactured: €700-1,200. Critical: address turbo failure immediately as debris can destroy engine and catalytic converter. Regular oil changes every 15,000 km maximum help prevent premature failure.
Suspension control arm bushings€600 - €1,200
Front bushings wear causing knocking, poor handling, uneven tire wear · more· less
Common wear item on B7 A4, typically needs attention around 80,000-120,000 km. Symptoms: clunking over bumps, vague steering, uneven tire wear. Most mechanics replace entire control arms rather than pressing out bushings. Aftermarket control arm kit (both sides): €400-600. Labor: €200-400. Total: €600-1,000 at independent, €1,000-1,200 at dealer. Upgraded Meyle HD kit: €420. Wheel alignment required after replacement (€80-120). Also inspect ball joints at same time.
Glow plug failure€200 - €500
Hard cold starts, rough idle, glow plug light stays on · more· less
Fairly common on higher mileage B7 diesels. Important: BLB/BNA engines use metal glow plugs, BRD/BRE/BRF use NGK ceramic plugs (white/silver seal) - do not mix types. Symptoms: preheating light stays on, rough cold idle, hard starting in cold weather. Risk: glow plugs can snap during removal on high mileage engines. Use torque wrench in reverse - if resistance exceeds 30 Nm, stop and seek specialist help. Parts: €15-20 each (4 plugs total). Labor: 1-1.5 hours (€100-150) if straightforward. If one snaps, cylinder head removal required (€1,000+). Professional replacement: €200-500 total. Sometimes the glow plug control module fails instead (€150-250).
High risk without balance shaft conversion
The B7 2.0 TDI is fundamentally a decent engine when properly maintained, but the balance shaft design flaw is a critical issue affecting roughly 1 in 3 cars. Verify balance shaft conversion has been completed before purchase, or budget €700-900 to have it done immediately. The 140 hp manual gearbox variant without DPF is the most reliable configuration. Avoid 2005-early 2006 models and Multitronic CVT transmissions unless 7-plate upgrade is confirmed. With the balance shaft sorted and regular maintenance, these can be dependable cars.
Pre-Purchase Inspection Checklist
General checks
Service history
Complete dealer or specialist records essential. Verify oil changes every 15,000 km maximum (not extended intervals).
Timing belt service
Must have documented replacement every 80,000-100,000 km or 5-7 years. Walk away if no proof.
Cold start test
Engine must be completely cold. Listen for rattling (balance shaft/flywheel warning).
Oil level and condition
Check dipstick. These engines can consume oil - low level suggests neglect or problems.
Test drive minimum 30 minutes
Include highway speeds. Get transmission and DPF up to operating temperature.
Specific for this vehicle
CRITICAL: Verify balance shaft conversion completed
Ask for receipts proving modified balance shaft installed. If not done, this is a €700-900 immediate expense or walk away. Look for KMB, modified hex shaft, or extended balance shaft in service records.
Listen for rattling on cold start
Start completely cold engine. Rattling that lasts more than 1-2 seconds indicates balance shaft or flywheel failure developing. Walk away.
Check for oil leaks around valve cover and vacuum pump
Look at valve cover edges and center bolts. Feel around vacuum pump (back top left of engine, silver). Oil presence = leaking gaskets.
Verify fuel injector recall completion (170 hp models)
Contact Audi dealer with VIN to confirm Siemens injector recall work completed on BRD/BRE engines.
Test for DPF issues (170 hp only)
During test drive, watch for DPF warning light, check power delivery is strong, no white smoke. Ask about driving patterns - short trips only = likely clogged DPF.
Multitronic CVT inspection (if automatic)
Verify 7-plate clutch upgrade completed (post-2006). Test for juddering at low speeds, rolling back on hills in Drive, jerky shifts. Any issues = walk away.
Flywheel test
When cold: light rattle for 1-2 seconds is normal. Persistent rattle or clutch pedal vibration = DMF failure imminent.
Suspension bushings check
Drive over speed bumps slowly. Clunking = worn control arm bushings (€600-1,200 repair).
VCDS/VAG-COM diagnostic scan
Essential. Check for stored fault codes in all modules, especially glow plugs, DPF, EGR, turbo boost, transmission.
Recalls and Technical Service Bulletins
Fuel injector recall (early 2.0 TDI PD engines)Contact Audi with VIN
Multitronic CVT 6-plate to 7-plate clutch conversionVerify completed on pre-2006
Balance shaft design flaw (not official recall)Verify modification completed
Brake pulsation / front brake noiseTSB available
Various electrical module faultsTSB available
Contact an Audi dealer with the VIN to verify all recalls completed. Most critical: injector recall (170 hp), Multitronic 7-plate upgrade (if CVT), and balance shaft conversion (though not an official recall, essential for reliability).
Warranty Status
Factory warranty (2 years)Expired on all B7 models
Extended warranty availabilityLimited for 15+ year old cars
Timing belt warranty periodTypically 12 months from service
All B7 A4 models (2005-2008) are well outside their original factory warranty. Some third-party extended warranties may be available but will exclude pre-existing conditions and known issues like balance shaft. Any timing belt/water pump service from a reputable garage typically carries a 12-month warranty on parts and labor.
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.