Volvo S80 auxiliary belt failure causing timing belt interference and potential engine damage due to lack of protection and faulty tensioner on Volvo S80

Some Volvo S80 owners report experiencing serious issues related to auxiliary belt failure, which can lead to timing belt interference and potential engine damage. This failure is a primary suspect for causing the timing belt to malfunction in interference-style engines, sometimes resulting from poor design or unfortunate circumstances. Owners have noted that if the timing belt breaks, there is a significant risk of internal damage, as pistons may collide with valves. In specific cases, such as with the 2007 S40 T5 AWD, a broken accessory belt caused the timing belt to slip out of sync with the camshafts, leading to potential bent valves. Additionally, the failure of the auxiliary drive belt can result in extensive damage to components like rocker arms, hydraulic lifters, and cylinder heads due to the timing belt jumping. It is essential for owners to address auxiliary belt issues promptly and adhere to regular maintenance schedules to prevent further damage to the engine.