I know what you are going through, I went through the same. As a last step I was going to go to the local bone yard and find a larger rad, as I said I stumbled on the solution with the belt. The after market temp gauges are cheap even Walmart sells them and they are very accurate, why not try one very easy to install, Give that a try just to put your mine at easy. Keeps us updated. As a last suggestion I wonder if the fins in the water pump dis-solve that way they did in the BMW 3 series cars.