Thermostat and Housing

What is an automotive thermostat and where is it located?

Thermostat sits between the engine and the radiator which helps to regulate the flow of a heat transfer fluid as needed, to maintain the correct temperature.
The thermostat is needed for the engine to keep its operating temperature. So its duty is to block the flow of coolant to the radiator until the engine has warmed up. When the engine is cold, no coolant flows through the engine. When you start your vehicle after the engine gets warm, the coolant within it gets hot as well, and because of this heat, the wax pellet inside of the thermostat melts. Once the engine reaches its operating temperature (generally about 180 degrees F), because of tension, it expands significantly and pushes the rod out of the cylinder, opening the valve, after that the hot coolant starts to flow through the engine and to the vehicle’s cooling system. The radiator cools down the coolant and sends it back to the engine. This helps to cool down the engine of the car as well, which prevents from the overheating. As the coolant gets cooled down as well, the wax returns to its previous position, and because of that the thermostat will partially or fully be closed, which will reduce the flow of the coolant. Because of this opening and closing system, the engine temperature is controlled.

How do I know if my thermostat needs to be replaced?

One of the main reasons why the thermostat becomes damaged is that the valve becomes stuck in its opening and closing position because of the wax build up. Or simply the debris gets inside and causes thermostat wear. If the thermostat is stuck closed, antifreeze won’t flow from the radiator , resulting in car overheating. One of the signs that it might be stuck in the closed position is the dashboard indicator. Either the dashboard temperature gauge reading in the red zone will show up, or applicable warning light will come on.
Another sign to this overheating because of the damaged thermostat can be if you hear a knocking sound in a steam heat pipe.
There is one way to check it if the thermostat valve is stuck closed. Just remove the thermostat with valve, put it in water with the thermometer, and raise the water temperature to about 195 degrees. If the valve is not opening, then it means that it is worn out. If you already removed the whole thermostat and checked the valve for its working or not working condition, and you found out that it is damaged, it is good to replace it and avoid harming other parts when your vehicle is overheating.
If the valve becomes stuck open, then coolant will flow endlessly, and the engine will never reach its operating temperature. It’s very noticeable in the winter time when your heater is not blowing hot air. Another sign that it is stuck opened is poor gas mileage, or it’s getting hard shifting to higher gears in the cars with automatic transmission.
Sometimes, the valve can get stuck partially open only. In this case, there will be a flow of coolant all the time, but not an optimal flow. So it will take longer to warm the engine up, your car will not operate properly, which can bring to the overheating after.

Can I replace an automotive thermostat myself?

Yes, if you have noticed that there is a problem with your thermostat , it’s easy to replace it by yourself, the difficulty can be only with the type of vehicle. The thermostat location can vary depending on the vehicle make and model. Sometimes you will need to remove other parts in your car before you reach to the thermostat. It’s always good to have a manual service of your vehicle in hand. Before you start removing something in your car, make sure that your car is cooled down, especially after overheating, and put some bucket under the leaking coolant, because it can be dangerous to pets and children.

What is a thermostat housing and where is it located?

In many internal combustion engines, the thermostat housing acts as the coolant outlet. It is usually located on the engine block or cylinder head. It contains the thermostat, which helps to control the engine’s operating temperature. From one side it’s connected by hoses to the engine, from the other side to the radiator, so it sits between the engine and the radiator.
The thermostat housing covers the thermostat, which helps to protect it from damage and the coolant leaking. In early years the thermostat housing was made of metal, but nowadays the manufacturers started to produce them in plastic because it is easy to manufacture the complex design and of course to reduce the price. Anyways, these plastic thermostat housings are easily breakable due to heat and over tightening fasteners or hoses while installing them.

How do I know if my thermostat housing needs to be replaced?

If the thermostat housing gets broken, it can cause the coolant to leak and damage of the thermostat itself. A coolant leak can lead to bad cooling and overheating, because of it the thermostat wears out. This overheating can lead to several other problems. If the coolant leaks it becomes acidic and can damage other parts of the vehicles nearby. If you see rust on the thermostat housing, be sure that it can be a sign that the thermostat cover is getting damaged. If it gets broken, all the debris comes inside of the thermostat and wears it out. And also, due to thermal expansion and contraction over time, the mating surfaces on the housing can warp or crack.

Can I replace a thermostat cover myself?

Yes, you can replace the thermostat housing cover by yourself, but again it depends on your vehicle because the placement of the thermostat and the thermostat housing cover can vary vehicle to vehicle. In some cars, you will need to remove other parts as well before getting to the thermostat. Again, always use a manual service before starting this process and don’t forget about safety!


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