Hi I'am new to this site and wish to ask a question about my old but loved 728i Auto on a V reg. . My Engine Temp Gauge gets to normal Op temp and sits there, but
then it drops towards the Cold by one segment. It then goes back to the middle again. It does this whilst I'am driving in all conditions, never goes above the normal Temp. I have hot air from the blowers and hot air when my gauge goes down towards the 1st segment towards the cold. I have no water/coolent leaks, coolent level never drops in the radiator, no mayo under oil filler cap (its clean and dry). Car drives like a dream and no warnings flash up and no messages on the Check List on the dash cluster. Can anyone
please tell me what is going on? Is there an air bubble in the cooling system, Thermostat failed or not working properly, faulty engine Temp sender etc ????