The larger generator will not cause higher output on its own. It only has a higher capacity, just like a hydraulic pump on a piece of construction equipment will only pump the volume of fluid needed, even though it has a higher capacity than the old one. To melt the plastic insulator at the output terminal you have to have current that is constantly very high, (which those parts are designed to handle), or there is excessive resistance which in this case can be way too small to measure accurately with an ohm meter. We can measure the RESULTS of that resistance in the form of "voltage drops", but one point we would need to put a meter probe is inside the generator and is not accessible. Voltage drop tests are commonly performed in starter circuits. Since your connections are new, we can assume excessive resistance in the connection is not the problem. That would leave a defect in the generator when it was rebuilt or something in the vehicle is drawing high current.
If the problem is with something the rebuilder did or overlooked, it is usually due a new inexperienced person doing the work and there will be a whole pile of them with the same problem until it comes to the company's attention. The failures will all occur the same way and in about the same time. You'll solve that by going to a different parts store.
If excessive current is the problem you can verify that with a load tester with an inductive amp probe but you would still have to know what "normal" is. If you have an obnoxious amplifier many kids use or if you've added a lot of lights or other accessories, those may draw high current.
If the voltage regulator is sensing low system voltage it will run the generator harder and that excessive current will go through the battery and overcharge it. Normally that is not a problem on GM systems because system voltage is monitored right inside the unit. The notable exception is on vehicles with digital instrument clusters. They are affected by minute changes in supply voltage so they tap off that point and run a circuit to one of the terminals in the generator's plug and monitor voltage there instead. A problem on the cluster or in that wire can cause overcharging. You'd find that by measuring battery voltage with the engine running and comparing that to the voltage on that terminal at the cluster. They should be the same.
Monday, July 16th, 2012 AT 8:41 PM