Dear friends of the well-kept Swedish automobile, I have noticed recently that the coolant temperature of my 900, 2.0 during the ride regularly sinks for a short time and lets me think about the function of the thermostat. However, after the cold start the engine gets warm quite quickly, so that the thermostat can not actually be completely failed. During the ride the thermometer is typically exactly horizontal and sinks more often in the short term (e.g. up to the point under 1/4 on the tank display .. mirror image) to climb up again a little later and adjust the horizontal position. This effect occurs about every five to ten minutes. Could this be normal (I don’t know where the coolant temperature is actually measured) or can such a thermostat become unappealing over time..?