Wrong forum, your Jetta is most likely mk5 or maybe mk4 but definitely not mk3 from 2004.
Seems that the coolant is not circulating. So you might have coolant pump failure or thermostat is permanently closed or radiator is clogged or sth else stops coolant from circulating. Start from temporarily removing thermostat, this is simple.
Yes, you should be in the mk4 forum, not the mk3 forum.
Most likely waterpump failure, but you didn't list which engine it has. 2.0 and 1.8T have timing belt driven waterpumps that known for the plastic impeller breaking free in the block. Time to service the timing belt, as well.
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