My 2000 Ironman has been overheating for a few summers, but only when using the A/C in hot temps. We tried EVERYTHING. Replaced thermostat 4 times, new water pump, new beefy radiator & hoses, new timing belt & pulleys, new fans & beefed up fan clutch, block tested for head gasket leak, changed temp sensor and even changed transmission fluid and cleaned A/C condenser. Turns out, over a very long and costly process of elimination, we had too much freon in our A/C due to a faulty A/C pressure gauge. Once the freon was adjusted to the correct specs, the overheating issue stopped!!! Overjoyed here, as tomorrow is forecast to be 105 degrees!