Audi A4 Timing Belt Tensioner Failure Warning Signs

The timing belt issue you describe sounds very familiar. I had a similar problem with my 2006 A4 1.8T last year, and I have some experience with basic automobile maintenance. The symptoms match exactly what I encountered, the inconsistent tension and that distinct noise during cold starts. The belt tensioner was indeed the root cause, but during the repair they also discovered the idler pulley needed replacement. The serpentine belt system requires proper tension to function correctly, and a failing tensioner can create these exact symptoms. The total repair came to 455 Euro, which included both parts and labor. The workshop completed the job in about 4 hours. They recommended replacing the timing belt while they were at it since they had already dismantled that area, which made sense from a maintenance perspective. The symptoms you describe could potentially lead to severe engine damage if left unaddressed, so its good youre taking action now. A failing belt tensioner can cause the timing belt to skip teeth, which is particularly risky for interference engines. To provide more specific advice, could you share: Your current mileage, When was the last timing belt service, Are you noticing any changes in engine temperature, Does the noise change with engine RPM

Last service was done at 48000 KM and now at 53896 KM. The tensioner pulley issue got worse over the last days. The engine noise is now constant even after warm up. After reading your response, I checked the serpentine belt again and noticed it looks a bit glazed in some spots. The timing belt looks fine, but you are right about replacing it while everything is apart. Did your mechanic mention if this is a common issue with these engines? The estimate I got is around 520 Euro for parts and labor, which seems in line with what you paid.

Thanks for the update on the mileage and current symptoms. Yes, this tensioner pulley failure is fairly common on these engines, especially around the 50-60k mark. The constant noise you're hearing now matches exactly what I experienced before I had mine fixed. The glazing you noticed on the serpentine belt is a clear sign of the tensioner pulley problems. When the belt tensioner fails to maintain proper pressure, the belt can slip, causing that glazed appearance. In my case, both the tensioner and idler pulley had worn bearings, which explained the noise persistence even after warm-up. The 520 Euro quote is reasonable considering current parts prices. For reference, my repair included: New belt tensioner, Replacement idler pulley, New timing belt, New serpentine belt The investment was worth it, my engine has been running smoothly for the past year with no belt-related issues. Since youre already noticing constant noise, I would recommend getting it fixed soon to prevent potential damage to other components in the belt drive system. Just make sure they check all the pulleys while doing the work, as worn pulleys can cause premature wear on the new belt tensioner and belts.

Thank you for sharing those details about the timing belt repair and cost. Your confirmation about constant engine noise is definitely concerning. After doing more research and seeing the symptoms match your experience, I will schedule the repair this week. The glazing on the serpentine belt combined with the belt squeal during cold starts seems to point directly to the tensioner pulley as the main issue. The 520 Euro quote makes sense given all the components that need replacement. I appreciate the heads up about having them inspect all pulleys while they are doing the automobile maintenance. Given that Im already at 53896 KM and experiencing these issues, replacing both belts along with the tensioner is the smart move for preventive maintenance. Better to handle it all at once than risk further engine noise or damage down the road. Will update once the repair is complete to confirm if it resolved everything.