Your Geo alternator is a well-engineered piece of machinery that ensures your car's electrical system has enough electricity, as well as ensuring that your battery is charged enough to start your car. But modern new electrical systems - with its multiple accessories like rear window defoggers and other features - can seriously strain a Geo alternator. In addition, running your engine on idle during the heat can tire out an alternator prematurely. That's because when the heat rises in an alternator, the electrical resistance rises. That cuts back on the charging capacity of your Geo alternator, since it is a safety measure to reduce the chance of the alternator overcharging the battery, or 'boiling' it. Some basic maintenance tips for your charging/electrical system: replace your battery every four years as a safety measure. If your battery is not a sealed unit, check fluid levels in each cell, and use only distilled water. Clean your battery connections at least once a year. When you put the terminals back on the battery after scrubbing them, coat the terminals with a layer of heavy grease or special purpose grease for batteries. Replace your alternator belts regularly, and refer to your owner's manual about when to do that task. Check to make sure the belts are tight and not slipping. If they are cracked or shiny on the side that faces the alternator pulley, then replace the belts. Common-sense maintenance measures with your Geo alternator will reduce headaches, cut back on your repair bills and keep you safe.