mystery over heat
 

working with an 01 jetta 1.8t swapped water pump and thermostat. the car will idle and sit at 190 all day but if you hit the highway or sit it at 2500 rpm the temp gauge walks up to 240. the overflow will level will settle down so i don't think it is the head gasket but this systems makes no sense to me any way.
thank you for any help
john