Mine had an eight inch pulley and whenever I punched it, I would lose a belt.

Then I went to the serpentine system, but there too, I would lose the belt.

So, I switched to a four inch crank pulley and no more belt jumping. Now when I come to a light, the amp gauge shows a discharge situation, however it more than compensates for the belt jumping I used to experience.

As for over heating, no problem, but then I have dual electric fans. If I had a pulley driven fan, it probably would heat up. But I have found that the water pump turns fast enough even now.

I don't know if a six inch pulley is available, but that might be the answer in our case.