Audi A4 B8 2.0 TDI 143bhp Known Faults
The B8 A4 TDI is a popular executive diesel with high fleet mileages. EGR, DPF and timing belt are the key maintenance watches.
What To Check Before Buying
- ✓Check service history — was oil changed regularly?
- ✓Look for blue/black smoke on startup and under load
- ✓Listen for rattles, knocking, or turbo whine
- ✓Test all electrics including windows, AC, and central locking
- ✓Check for DPF warning light or recent regenerations
- ✓Inspect for rust underneath and around wheel arches
- ✓Request a pre-purchase inspection by an independent mechanic
Known Faults
Timing Belt Failure
CriticalThe B8 A4 2.0 TDI uses a timing belt with a 140,000-mile service interval. Many specialists recommend 100,000 miles. Belt failure is catastrophic on this interference engine.
EGR Cooler Failure and Coolant Loss
SevereEGR cooler failure is common on the B8 A4 TDI. Internal corrosion allows coolant to leak into the intake — initially causing rough running and white smoke.
Turbocharger Failure
SevereTurbocharger failure on the B8 A4 TDI mirrors the wider VAG TDI pattern — oil sludge in the feed pipe causes bearing failure, often presenting as a sudden loss of boost.
Injector Failure
SevereHigh-mileage A4 B8 TDIs suffer injector wear, causing rough running, smoke and diesel contamination of engine oil.
DPF Blockage
ModerateThe A4 B8 TDI is frequently used as a company car on short local journeys rather than motorway runs. DPF blockage is the most common ownership complaint.
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