Hallo all, To the vehicle gurus... we have been having this debate after a vehicle overheated. At first we thought it was a faulty sensor, so we removed that... Then the situation got out of hand and the mechanics advised that the Thermostat was the problem, and it is common knowledge to remove the thermostat when it comes from winter countries to our good old sub-sahara.. This overheating problem occurs in rainy or cold situations - dont know why. But never when its hot, so on a level, the mechanics could be right. After removing the thermostat and reinstalling the heat sensor, the vehicle seems fine and does not overheat - however, I came across the article below on the net [who do we believe? experienced mechanics, or those who know why the thermostat was installed in the first place?] : Q: Can running without a thermostat cause overheating I was told that if the water circulates too fast it will not cool properly Is this possible and how? Running your engine without a thermostat will cause it to run hot. An engine will run cooler initially without a thermostat. After that IT WILL NOT! Why you ask? Again, physics. An engine running without the restriction of the thermostat in the system (remember, even when it's wide open there's still some restriction in the system caused by the thermostat's small opening) will not keep the coolant in the radiator long enough for the radiator to 'radiate' the heat. That is, the coolant must stay in the radiator for a certain amount of time to dissipate some of the heat it has absorbed from being in the engine block. The coolant is in the block. It's hot. It moves to the radiator and gets rid of some of the heat. If it moves through the radiator too FAST, without the restriction of the thermostat body, it won't get rid of as much heat. Basic Thermodynamics at play. http://wiki.answers.com/Q/Can_running_without_a_thermostat_cause_overheating...