By: Parts for Trucks
Too many electrical problems are being misdiagnosed and blamed on defective alternators. Learning how to correctly diagnose charging system problems reduce unnecessary down time and return trips to the shop.
A loose drive belt is a leading reason that alternators fail to develop the proper output. A drive belt tension gauge is inexpensive and easy to use, but too many mechanics check belt tension by pushing the belt with their fingers.
Unless the mechanic is experienced, that method may lead to a false indication of the belt being tight enough. In reality, it might be slipping on the pulley at high engine speeds. One quick way to determine if the belt has been slipping is to check it for glazing.
At the other end of the spectrum, a belt that is too tight generates damaging heat. The heat will travel from the alternator pulley through the shaft and into the alternator to attack bearing grease. Not designed to withstand such heat, the grease will break down and allow bearing damage.