Although there does not exist spring failure within dual mass flywheel, the service life of OEM dual mass flywheel proves to be as same as that of clutch, which means flywheel should also be replaced when clutch wears out. If only clutch is replaced, you are likely to be faced with flywheel issue due to flywheel’s weakened springs. That is the reason why mechanics usually recommend replacing dual mass flywheel and clutch at the same time, notably if flywheel has over 120000 km on it. At this point, flywheel should be treated as a worn item, like clutch.
Surface wear turns out to be another reason for replacing dual mass flywheel. Under daily clutch operation, dual mass flywheel’s friction surface wears, like ordinary flywheel. The surface of clutch may be rough, grooved, cracked or have hard spots. Slight scoring and grooving can be accepted. By comparison, if surface is warped, cracked or has hard spots, the flywheel must be changed.
Due to double-piece design, it is almost impossible to resurface dual mass flywheel which has rough or grooved surface. In order to resurface dual mass flywheel, it has to be taken apart, hence the secondary flywheel can be remachined. Subsequently, it has to be rebuilt with new springs and reassembled with same tolerance like before to make it work properly. Most kinds of dual mass flywheel can not be disassembled or serviced, thus replacement is highly recommended if it wears or makes noise.
For replacement cost, it is very costly. The price of flywheel alone is approximately $950. However, if a brand new clutch, clutch disk and labor are included, trust me, you do not wanna see the figure showed on bill.