About this part
What it does. Dayco POLY RIB BELT, DAYCO Dayco 311-5080550 drives engine accessories such as the alternator, water pump and air-conditioning compressor.
Symptoms that point to this part
- Squealing on cold start
- Visible cracking or glazing
- Accessories losing power
Fitment. Catalogued as fitting 2019–2021 BMW M2, 2019–2020 BMW M4. Engine, sub-model and trim can narrow fitment further, so check those attributes on the listing before ordering.