The Stovebolt Site Forums The Shop Area General Truck Talk Thermostat,no thermostat, that is the question

You need a thermostat. Engines run best at a certain temperature, and the thermostat keeps the engine at that temperature. So when you start out cold, the coolant does not circulate to any great degree, which lets the engine warm faster. And yes, without a thermostat, the engine can run too hot, because the coolant is circulating too fast.