Heat gauge when I start the car engine will heat up, gauge will hit half way mark then drop. after that the gauge will rise and fall about every 3-5 mins from the 1/4 mark and down when you are going about 80+kms, when in park and idle... heat gauge rise and fall normal, takes about 1/2 hour or so in cool weather (I.E. +5) things I have replaced include...head, head gasket, thermistat, radiator, rad. fluid, rebuilt some of the part ( can not buy new anymore) the car dose not over heat, the gauge is just screwed up