Audi SQ5 Belt Squeal Signals Failing Tensioner Fix Need

Had the same belt tensioner issue on my S4 3.0T last year. The timing belt started squealing during morning starts and got progressively worse over two weeks. The root cause was a failing belt tensioner combined with a worn idler pulley. These components work together to maintain proper tension on the timing belt. When they start failing, the belt cant maintain consistent tension, leading to that distinctive squeal and sluggish belt operation youre describing. Left unaddressed, this can lead to serious engine damage. In my case, the mechanic found the tensioner bearing was severely worn, which was causing improper belt alignment. The repair involved replacing the belt tensioner, idler pulley, and timing belt as a complete set, since these components wear as a system. The job took about 6 hours at the shop. Given your mileage and symptoms, Id strongly recommend getting this addressed soon. A failed timing belt can cause catastrophic engine damage on these engines. Make sure whoever does the work is familiar with VAG engines and uses OEM or equivalent quality parts for these critical components.

Thanks for sharing your experience. I had pretty much identical symptoms with my SQ5 last winter. The serpentine belt started making that awful squealing noise during cold starts too. The timing belt and tensioner replacement fixed it completely. Just wondering, how much did you end up paying for the complete repair? Also, has your engine performance stayed solid since the fix? My car runs great now, but Im always curious to hear about long-term reliability after these kinds of repairs.

Had the full repair done, replaced the worn belt tensioner, serpentine belt, and idler pulley as a complete set. Total cost came to 455 Euro for parts and labor. The technician confirmed the bad belt tensioner was the root cause, exactly matching the symptoms you described. Engine has run flawlessly since the fix, no more squealing or belt drive issues for over a year now. The timing belt tension stays perfect, and cold starts are completely quiet. Definitely worth addressing these belt system components as a complete set rather than piece by piece. Performance has actually improved slightly, likely because the belt drive system is now operating at optimal tension. Regular maintenance on these belt components really pays off in the long run and helps prevent more serious engine problems.

I finally got it fixed last month and wanted to share my experience. After getting recommendations from a I took it to a different mechanic who specializes in engine performance issues. The entire serpentine belt system needed attention. The total repair came to 680 Euro, which included a new tensioner pulley, serpentine belt, and idler pulley. More expensive than expected, but the automobile maintenance quality was worth it. The mechanic showed me the old parts, the tensioner was completely shot and the bearing was making that awful noise. The job took around 4 hours, and the engine noise disappeared completely. Cold starts are smooth now, no more squealing. Its been a month of daily driving, and the engine performance feels noticeably better. The belt drive is working perfectly, and Im glad I didnt wait any longer to get it fixed. Definitely learned my lesson about addressing these issues promptly, a failing belt tensioner isnt something to ignore. Next time Ill catch it during regular maintenance before it gets this bad.