Excessive belt tension will cause damage to the alternator and water pump pulley bearings, while, on the other hand, loose belt tension will produce slip and premature wear on the belt. Therefore, be sure to adjust the belt tension to the proper level.
To adjust the tension on a drive belt, loosen the adjusting bolt or fixing bolt locknut on the alternator, alternator bracket or tension pulley. Then move the alternator or turn the adjusting bolt to adjust belt tension. Once the desired value is reached, secure the bolt or locknut and recheck tension.