Many times this is masked by engine noise on warm up. But if you worry about temps, get something to plug in the OBDII port so you can see temps real time. For all we kow you could be the one Disco within wifi range of the dealership taht has been programmed by stealth to throw new codes next week. Or inreality, you might detect a problem before the gauge, which is more optomistic than politicians and moves slower than legislation, will show it to you. By the time it shows problem, problem is bigger problem.