Hard to see the future is. But sometimes an electrical problem like this can be traced to corroded cables at the battery. I don't mean just at the connector posts, but further up inside the cable. I had a positive cable which looked great, but under the plastic insulation, about half the copper had turned to green powder for a lenght of 3 inches. You might also want to inspect the heavy jumper cable which runs between the battery negative post and the car chassis as well as the heavy cable which jumps between the chassis and the engine block. Now I don't believe corroded cables alone could cause the car to overheat; unless perhaps there was insuficient current to run an electrically driven radiator fan. All your high power stereo stuff should connect directly to the battery and not share any circuits with other gear. My old 68 AMC AMX had an amp meter in the battery circuit. One glance at the meter would tell you exactly what's happening in the charging circuit and battery. Today they just give you a meaningless light. Good Luck. Tod
Resistance is Futile.