overheating and confused

[Loud Pipes]

2004 Tiburon, 2.0L, manual trans, a/c, 89k miles

I could really use help. Tiburon is overheating after driving 20 min. It operates fine during the first 20. The radiator is new, the thermostat is working, the upper radiator hose gets hot, the lower stays cool. The overflow is full and the line from the radiator cap is clear. Fluid is topped off, and will spill out of the overflow when too hot. Both cooling fans are working properly.

The engine does not seem to be getting too hot, but the coolant does. The radiator seeps steam out of the cap when the temp gauge gets to the red zone. But other than that, the car runs fine.

I thought about a head gasket, but I cannot see any leaking when it is overheating and I don't have any steam coming off of the block anywhere. I thought about the water pump, but I would think that if it seized it would fry the timing belt. But I am not that experienced and figure I am missing something here. Any ideas? Could really use the help.

Thanks!

[Loud Pipes]

never mind - thermostat did the trick!