1991 Mercury Capri Q&A
1991 Mercury Capri Question: Fan Belt noise?
Either one or more of your belts is worn and probably loose and you will need a shop to replace one or more to eliminate the noise also they can check your power steering pump alternator etc at the same time. You can get a estimate for belt replacement here https://repairpal.com/estimator?car_type_id=5847 and locate a shop near you here https://repairpal.com/directory?address=89110&car_brand_names=Mercury - hemicuda
could be your aftermarket belt doesnt quite have the same groves as the original....it'll wear down or just get one from Napa - Pdaddy1