A thermostat is simply a spring loaded plate that opens when the coolant tempurature reaches a certain point (Coolant absorbs the heat from the block as the engine is running). When the temp reaches 185 - 215 degrees,depending on the thermostat, the thermostat opens and lets the hot coolant out of the engine block. The coolant is pushed out by a water pump that is always running when the engine is running. The water pump is pushing cool fluid from the other side of the engine (coming from the radiator) while the hot coolant is being pushed into the radiator to cool off. If you remove the thermostat, then the coolant is just flowing thru the engine. While more than likely this will still remove most of the heat from the engine block, you will not have any heat for the cabin heater. You also may cause an issue with the cooling system, i.e., radiator, water pump, radiator hoses,etc., because there will not be the correct pressure in the cooling system. The radiator hoses may collapse and you may build air pockets in the cooling system. In short, you can drive the vehicle, but you may be causing yourself much more expense in the short to long run.
Posted on August 20, 2012