[BNaylor]

Follow the upper radiator hose to the thermostat. The engine coolant temperature sensor (ECT) is located right next to it on the lower intake manifold. You'll see the electrical connector. What is your temperature gauge reading?

The sensor can be ohmed out with a digital multimeter to check calibration. For now with engine off, disconnect the ECT. Start engine. The cooling fans should turn on. That will illiminate the PCM ouput to the cooling fan relays in the engine compartment fuse box. Other than that a possibility of a bad ECT sensor or the thermostat staying closed.

When coolant flows out the tank overflow that means cooling system pressure is too high and exceeding the 15 psi rating of the cap due to overheating.

Also, check to make sure there is no coolant in the engine oil or oil in the cooling system to check for the possibility of bad intake manifold gaskets.