With my car, low speed kicks on before half on the guage. About halfway between half and 3/4 it goes on high. I also replaced the temp guage sender after my rebuild 3 months ago as it looks like my old one was giving a bad reading and caused my engine to run at high temps for a few weeks. Small crack on head becaome of this. I noticed my radiator temp switch had gone bad and it cost me. The only issue I have, which might not be an issue, with gauge is that in stop and go traffic, it stays pretty much at noon and maybe a needle width past but while driving it drops almost closer to 1/4. I might have a stock open tstat. I did check it during the rebuild before installing it as it is only 3 years old.