oscillation of energy equation in steady state heat transfer
 

hi everybody
I have a problem with my simulation and I hope that there is some person that can help me.
before everything I truly apologize for my lack of skill in writing English well.
I'm simulating the heat transfer and material flow in FSW welding by using a UDF.
in UDF the coordinate system defined how I should put the center of the tool in them. but when I start to simulate the energy equation starts to oscillating in the wrong rang. (0k to 5000k) that the fluent put this limit by default. but in this way when I take contour the shape of the contour is right and it's like the reality.
in another way when I put the coordinate system at the first of the workpiece the energy equation has a normal act to convergence and the rang of temperature is right. but when I take the contour its wrong.

I want to ask is there anybody to know why this happens and what should I do?
for your know, my work is steady-state, pressure-based, simple method simulation.
I send my pictures and my UDF in case if anyone wants to see.