The thermostat is a valve that controls the flow path of the coolant. It is an automatic temperature regulating device, usually containing temperature sensing components, through thermal expansion or cold contraction to open and close the flow of air, gas or liquid. The function of the thermostat is to keep the engine from overcooling. For example, after the engine is working normally, the temperature of the engine may be too low if there is no thermostat when it is driven in winter. At this time, the engine needs to temporarily stop water non-circulation to ensure that the engine temperature is not too low. Generally, the coolant of the water cooling system flows in from the body and flows out from the cylinder head. Therefore, the thermostat is generally installed at the water inlet where the water pump is installed. This is the junction of hot and cold water, and the most sensitive place. Its opening temperature is the temperature of the cooling water in the engine block, while its closing temperature is the temperature of a small part of the cold water that flows from the radiator through the thermostat into the cylinder block. The volume and range of its adjustment are relatively compared. It is small, so its fineness of adjustment is relatively fine, and it will not cause large fluctuations in the temperature of the engine block to make the engine run smoothly. Symptoms of a bad thermostat. Engine Very Hot or Cold. We already know that the thermostat controls the engine temperature. If it’s too hot or too cold, chances are that the thermostat is not doing its job properly and it needs to be replaced. There could also be a problem with the radiator, or the coolant might have run out, so you need to check all the possibilities before you contemplate changing the thermostat. The thermostat must ensure the engine remains at its operating temperature. It can do that by allowing more or less of the coolant from going inside the block. If the thermostat malfunctions, it will not be able to regulate the temperature levels as well as it used to and that will result in erratic temperature changes. The only thing stopping the coolant from reaching the engine is the thermostat. If the thermostat valve spring is completely shut, the coolant won’t be able to pass. When this happens, the coolant will start to leak from several places. If you can spot a leak inside the engine bay or a patch of liquid beneath your car then the thermostat may have gone bad. If this happens, you will need a car thermostat replacement. Know how to replace the Thermostat. Locate your thermostat if you haven’t already done so. Place a bucket under where you’re going to be working. Pull off the hose. Remove the bolts that hold the thermostat housing in place and lift out the old thermostat. Lay the new gasket in place. Drop in and secure the new thermostat. Replace the hose and hose clamp. Replace whatever fluid ran out of the hose by pouring it from the container into the radiator fill hole or coolant reservoir. Immediately, we will give a satisfied solution. ABS Wheel Speed Sensor. Mass air flow sensor.