VW Polo Guzzling Gas: VANOS Issues Explained

As someone with moderate experience working on VWs, I had a similar issue with my 2010 VW Golf 1.4 TSI. The check engine light came on and I noticed increased fuel consumption, just like you described. After diagnosis, it turned out to be a faulty inlet camshaft solenoid valve. The repair involved replacing the solenoid valve and cleaning the surrounding area. The total cost was 250€ including parts and labor. The actual repair took about 3 hours at my regular workshop. They mentioned timing chain tension should also be checked when dealing with these symptoms, as it can sometimes be related. The engine misfire symptoms completely disappeared after the fix, and fuel consumption returned to normal. The check engine light hasn't come back since. What diagnostic codes is your car showing? This would help narrow down if your issue is similar to what I experienced. Also, have you noticed any rough idling or drop in power during acceleration? These details would help determine if we are dealing with the same VANOS-related problem. Things to check: Engine fault codes, Current mileage, Maintenance history, Any unusual engine sounds, Performance changes during cold starts

Thanks for sharing your experience. My last service was done 3 months ago at 77955km. The symptoms match exactly what you described, especially the rough idling and increased fuel consumption. The diagnostic scan showed P0011 code, suggesting timing over-advanced issues. No unusual sounds during cold starts, but definitely feeling power loss during acceleration. The engine seems to struggle most when the oil is cold. The workshop quoted 350€ for VANOS solenoid replacement. A bit concerned about potential oil sludge buildup affecting the inlet camshaft timing. Would you recommend a full oil system flush before the repair?

After completing the VANOS solenoid replacement on my Golf, I can definitely say an oil system flush would be worthwhile in your case. The P0011 code matches what I experienced, and the cold oil symptoms strongly suggest timing control issues. My mechanic found significant oil sludge buildup when replacing my inlet VANOS solenoid. We did a complete oil system flush, which helped restore proper oil flow to the VANOS system. The total cost increased by about 80€, but it was worth it to prevent future timing issues. The power loss during acceleration completely resolved after addressing both the oil sludge and VANOS solenoid. The engine misfire symptoms disappeared, and fuel consumption dropped back to normal levels within the first tank after repair. The 350€ quote sounds reasonable considering current parts prices. Make sure they check the timing chain tension during the repair, mine needed slight adjustment while they were in there. This combined approach solved all timing-related issues for me. Even at 77955km, oil sludge can accumulate if the oil service intervals were stretched. The full system flush will give the new VANOS solenoid the best chance of proper operation.

Thanks for the detailed responses. I just got my car back from the workshop and wanted to share the outcome. You were right about the oil system flush, they found significant sludge buildup when servicing the VANOS system. Final repair bill came to 430€ including the VANOS solenoid replacement, oil system flush, and timing chain inspection. The check engine light is now off and fuel consumption has returned to normal. Power delivery is smooth again, especially during cold starts. The mechanic showed me the old solenoid which was heavily contaminated. They recommended staying strictly on schedule with oil changes to prevent future VANOS failure. The engine misfire symptoms are completely gone and the car runs like new again. Really glad I opted for the complete service rather than just the solenoid replacement. The timing chain tension was slightly off but they adjusted it during the repair. Definitely worth the extra cost for the peace of mind.