Audi S6 Diesel Performance Drop with Blue Smoke Issue

Had almost the same issue with my Audi A6 3.0 TDI from 2018. Have some experience working on diesels but leave major repairs to professionals. The symptoms match what I experienced, engine light, reduced power, and smoke from exhaust. My DPF cleaning attempts through forced regeneration drives did not solve it. Workshop diagnostic confirmed a completely clogged diesel filter that was beyond cleaning. Total repair cost was 1550 Euro including: New DPF unit, Installation labor, System reset, Basic checks Vehicle was in the shop for 2 days. Since the repair, fuel efficiency improved noticeably and no more smoke or warning lights. To help diagnose your case better, could you share: Build year of your S6, Current mileage, Driving pattern (city/highway split), Last vehicle inspection date, Previous DPF regeneration attempts These details would help determine if you might still get away with a cleaning procedure rather than full replacement.

Just had my last service completed at 31401 KM checking all filters. Experiencing the exact same symptoms you described. My mechanic initially attempted DPF cleaning which temporarily fixed the backpressure issues, but the problem returned within a week. The diesel filter replacement ended up being necessary due to excessive soot buildup, despite the relatively low mileage. Cost was 1890 Euro including system diagnostics, new filter, and labor. Vehicle inspection confirmed this was the right call since the old filter showed signs of internal damage. After replacement, power delivery is back to normal and no more smoke issues. The high cost was worth it considering the potential damage a clogged DPF could cause to other engine components.

Thanks for the update on your S6 repair. My experience with the A6 matches yours exactly, the DPF cleaning only provided temporary relief before the symptoms returned. After spending money on repeated cleanings, replacing the diesel particulate filter was ultimately the only permanent solution. The repair cost difference between our cases makes sense given the S6 specific parts. The investment is definitely justified, as a faulty DPF can lead to increased fuel consumption and potentially serious engine damage if left untreated. The most telling sign that replacement was necessary in both our cases was the quick return of symptoms after cleaning. When the exhaust system starts showing these issues at relatively low mileage, it often indicates an underlying problem beyond normal soot buildup. Since the repair, have you noticed the same fuel efficiency improvements I experienced? My consumption dropped by about 0.8L/100km after the new DPF installation. The engine also feels more responsive, especially during cold starts. Remember to maintain regular high-speed driving sessions to help prevent future DPF clogging. This helps ensure proper regeneration cycles and extends filter life.

Great to hear back from everyone regarding similar experiences. Yes, my fuel consumption has also improved since the repair, seeing about 0.7L/100km better efficiency, very close to what you mentioned. The engine response is definitely crisper now. The exhaust system works perfectly with no more smoke issues. My mechanic explained that the backpressure readings are now within normal range, confirming the diesel filter replacement was the right choice. While the regeneration attempts saved some money initially, going straight for replacement would have been more cost-effective in the long run. Learning from this experience, I now make sure to include more highway driving to maintain proper DPF function. The engine light has stayed off and power delivery remains strong. While the repair cost was significant at 1890 Euro, the improved performance and prevention of potential engine damage made it worthwhile. Thanks everyone for sharing their knowledge and helping me understand these symptoms better. Having real-world repair experiences really helped confirm my decision to proceed with the full replacement.