As you know, a car engine heats up during operation. And its excessive temperature is fraught with very serious troubles, up to and including failure. On the other hand, a cold engine has more fuel consumption.
A device called a thermostat is designed to find a balance between these two extremes and maintain an optimal temperature of the power plant. The driver can independently determine the degree of performance of this device using several simple methods.
How a car thermostat works
The engine cooling system has 2 circles: large and small. Until the coolant has time to heat up, it flows in a small circle, without entering the radiator, and when a certain temperature value is set, it switches to a large circle. The thermostat included in the structure of the heat removal complex sets the cooler one of these two routes.
The functioning of this apparatus is based on the well-known law of physics, which states that under the influence of heat, the size of an object increases. The thermostat design is pretty simple:
- a cylinder with a special composition including wax, bulk copper, graphite and aluminum;
- a rod inside this cylinder;
- valve mated with the stem and opening access to the radiator.
Antifreeze transfers the thermal energy received from the engine to the components inside the thermostat cylinder. When heated, this composition increases in volume, forcing the stem to move, and with it the valve, which, in turn, opens the way for the coolant to the radiator.
Curiously, machines with a dual circuit liquid cooling system are often equipped with two thermostats. One of these elements maintains an 87-degree temperature in the cylinder head circuit during engine operation. And the second, located in the outline of the block itself, gives this parameter a value of 105 degrees.
With this option for thermal management, the power plant is cooled better, which makes it more powerful. This technology has found its application in the production of highly efficient turbo engines.
Where is the thermostat
Before you start researching the performance of a thermostat, you need to find it corny. However, this is quite simple to do.
First, you need to open the hood and find the upper radiator hose under it - a pipe with a large diameter that connects this cooling element to the motor. Just in the area where this pipe connects to the engine, the thermostat is usually hidden.
However, in some models of cars, it may be identified with some other haven, so when searching for this device it is recommended to use the documentation for the existing car.
Signs of a broken thermostat
In the community of motorists, the expression "the thermostat is stuck" is sometimes found. Since the function of this device is to open one of two routes for the movement of antifreeze, such words may imply the following types of breakdowns:
- The thermostat prevents the cooler from reaching the radiator. This situation threatens overheating of the power plant, but the dashboard must report this. Further failure to take measures can cause damage to both individual parts of the engine and the whole unit.
- The thermostat "stuck" when it is open, and therefore antifreeze constantly runs through the radiator. In warm weather, such an outrage will not lead to serious troubles, but in the cold it will be problematic for the engine to warm up to the desired condition. The result is a significantly increased fuel consumption and a weakly heating car stove.
The main reasons for limiting the mobility of the thermostat valve are considered to be scale contamination of the device and the formation of rust. Under such conditions, the thermostats are fixed in a certain position, most often open, fully or partially.
Often, motorists themselves provoke a quick breakdown of the device, for a long time without changing the cooler in the car or filling in a low-quality and cheap product from an unknown manufacturer. Others, when diluting concentrated antifreeze, use ordinary water instead of distilled water, during the process of replacing the coolant, they do not rinse the cooling complex, etc.
The most common vulnerabilities of thermostats include the loss of the required qualities by the contents of the cylinders. For example, a decrease in the expandability of this composition will mean a decrease in its limiting volume. For this reason, the filler may not have enough pressure to fully open the valve or at least move it from its place. Excessive heating of the cooler is ensured in this case.
But even more insidious is the periodic valve wedging, or the so-called "thermostat sticking". The device is working normally, then it junk, and therefore it is rather difficult to recognize the "ailment". But if it is found, it is recommended to examine the cooling complex and, without waiting for the aggravation of the situation, change the thermostat.
Checking the thermostat "on the fly"
If suspicious symptoms appear in the thermostat, it can be examined without removing it from under the hood and without bringing the car to the service station. Even a novice car enthusiast can perform this procedure, the main thing here is to be able to start the car, open the hood and remove the radiator cap. This check can be done in several ways:
- Start the engine, wait two minutes, open the hood and feel the upper radiator hose. When the thermostat is closed, this pipe should not heat up. But when the motor gains enough heat, a normally working thermostat will start a large circle, in other words, send antifreeze along the radiator. This usually happens at a coolant temperature of 75-85 degrees, but this value is largely determined by the thermostat model. In any case, the hose connected to it must be hot. If it does not heat up, then the device is faulty.
- Start the engine and note the time before the heat from the stove begins to enter the passenger compartment. If the warm-up lasts more than 5 minutes, the chances are high that the thermostat will not close. As a result, the coolant flows through the radiator, and the power plant cannot reach the desired temperature.
- Open the hood, remove the radiator cap and start the car. Until the power plant has warmed up, a working thermostat will not start the cooler into the radiator, therefore, in the latter, the coolant level should remain unchanged. The motor will warm up - the thermostat will open, and then turbulence will be found in the radiator.
It is worth noting that it is unlikely that it will be possible to reanimate an inoperative thermostat. Better to buy a new one right away.
Experiments in the kitchen to check the thermostat
If the engine overheats in the car or the stove heats up weakly, but the thermostat both opens and closes, then it is advisable to figure out whether this device works in the correct temperature range. For which you still need to remove it from under the hood.
It is necessary to dismantle the thermostat from a cold engine, and the cooler must also cool down properly. Disconnect the negative battery cable, drain part of the antifreeze to prevent it from spilling when disconnecting the upper radiator pipe. Then, from the engine side, we disconnect the hose itself. Finally, remove the thermostat and transfer it ... to the kitchen.
We place the device in a container with cold water and a thermometer. Make sure that the thermostat is closed and does not touch the walls or bottom of the vessel.Then we put this structure on the stove and subject it to heat up to the operating temperature, usually indicated on the thermostat housing. When it is reached, the valve will start to open. Then we remove the device from the water and let it cool down to room temperature. This process must be accompanied by automatic closing of the valve.
Ignoring temperature changes by the thermostat indicates its unsuitability. But if the device has done everything as it should, then the reason for the excessive heating of the motor lies in something else. For example, in a small amount of coolant or problems with the drive belt.
Features of the thermostat operation
The ability to open completely or partially allows the thermostat to quite effectively and flexibly maintain the optimal temperature of the internal combustion engine under various modes of engine operation. Moreover, the thermostat reduces the amortization of the components of the power plant and the toxicity of exhaust gases.
Do not neglect the control of the state of the thermostat itself, since replacing this device will cost much less than repairing the engine. Moreover, in some cases, a failed motor is no longer possible to reanimate.
Sometimes, when a thermostat breaks down, car owners remove it without replacing it with a new one. Perhaps this is not a very good move, since a cold engine does not work efficiently, and chronically slow warming up leads to a reduction in the life of the engine. The most popular and reliable thermostat manufacturers are Gates, Wahler and Vernet.
Conclusion
Although deviations in engine temperature from the norm can be caused by many different factors, it is the thermostat that should be checked first of all with such a malfunction. Moreover, this is not so difficult to do - the work does not require any special knowledge or tools and will not take much time. At the same time, it is not at all necessary to remove the device from the engine for express diagnostics.
|| list |
- How a car thermostat works
- Where is the thermostat
- Signs of a broken thermostat
- Checking the thermostat "on the fly"
- Experiments in the kitchen to check the thermostat
- Features of the thermostat operation
|| rss | An automobile engine, as you know, heats up during its operation. On the other hand, a cold engine has more fuel consumption.
A device called a thermostat is designed to find a balance between these two extremes and maintain an optimal temperature of the power plant. The driver can independently determine the degree of performance of this device using several simple methods.
How a car thermostat works
The engine cooling system has 2 circles: large and small. The thermostat included in the structure of the heat removal complex sets the cooler one of these two routes.
The functioning of this apparatus is based on the well-known law of physics, which states that under the influence of heat, the size of an object increases. The thermostat design is pretty simple:
• a cylinder with a special composition including wax, bulk copper, graphite and aluminum;
• a rod located inside a given cylinder;
• valve mated to the stem and opening access to the radiator.
Antifreeze transfers the thermal energy received from the engine to the components inside the thermostat cylinder. When heated, this composition increases in volume, forcing the stem to move, and with it the valve, which, in turn, opens the way for the coolant to the radiator.
Curiously, machines with a dual circuit liquid cooling system are often equipped with two thermostats. And the second, located in the outline of the block itself, gives this parameter a value of 105 degrees.
With this option for thermal management, the power plant is cooled better, which makes it more powerful. This technology has found its application in the production of highly efficient turbo engines.
Where is the thermostat
Before you start researching the performance of a thermostat, you need to find it corny. However, this is quite simple to do.
First, you need to open the hood and find the upper radiator hose under it - a pipe with a large diameter that connects this cooling element to the motor. Just in the area where this pipe connects to the engine, the thermostat is usually hidden.
However, in some models of cars, it may be identified with some other haven, so when searching for this device it is recommended to use the documentation for the existing car.
Signs of a broken thermostat
In the community of motorists, the expression "the thermostat is stuck" is sometimes found. Since the function of this device is to open one of two routes for the movement of antifreeze, such words can imply the following types of breakdowns:
• The thermostat prevents the cooler from reaching the radiator. Further failure to take measures can cause damage to both individual parts of the engine and the whole unit.
• The thermostat "stuck" when open, and therefore antifreeze constantly runs through the radiator. The result is a significantly increased fuel consumption and a weakly heating car stove.
The main reasons for limiting the mobility of the thermostat valve are considered to be scale contamination of the device and the formation of rust. Under such conditions, the thermostats are fixed in a certain position, most often open, fully or partially.
Often, motorists themselves provoke a quick breakdown of the device, for a long time without changing the cooler in the car or filling in a low-quality and cheap product from an unknown manufacturer. etc.
The most common vulnerabilities of thermostats include the loss of the required qualities by the contents of the cylinders. Excessive heating of the cooler is ensured in this case.
But even more insidious is the periodic valve wedging, or the so-called "thermostat sticking". But if it is found, it is recommended to examine the cooling complex and, without waiting for the aggravation of the situation, change the thermostat.
Checking the thermostat "on the fly"
If suspicious symptoms appear in the thermostat, it can be examined without removing it from under the hood and without bringing the car to the service station. This check can be done in several ways:
• Start the engine, wait two minutes, open the hood and feel the upper radiator hose. If it does not heat up, then the device is faulty.
• Start the engine and note the time before the heat from the stove begins to enter the passenger compartment. As a result, the coolant flows through the radiator, and the power plant cannot reach the desired temperature.
• Open the hood, remove the radiator cap and start the car. The motor will warm up - the thermostat will open, and then turbulence will be found in the radiator.
It is worth noting that it is unlikely that it will be possible to reanimate an inoperative thermostat. Better to buy a new one right away.
Experiments in the kitchen to check the thermostat
If the engine overheats in the car or the stove heats up weakly, but the thermostat both opens and closes, then it is advisable to figure out whether this device works in the correct temperature range. Finally, remove the thermostat and transfer it ... to the kitchen.
We place the device in a container with cold water and a thermometer. This process must be accompanied by automatic closing of the valve.
Ignoring temperature changes by the thermostat indicates its unsuitability. For example, in a small amount of coolant or problems with the drive belt.
Features of the thermostat operation
The ability to open completely or partially allows the thermostat to quite effectively and flexibly maintain the optimal temperature of the internal combustion engine under various modes of engine operation. Moreover, the thermostat reduces the amortization of the components of the power plant and the toxicity of exhaust gases.
Do not neglect the control of the state of the thermostat itself, since replacing this device will cost much less than repairing the engine. Moreover, in some cases, a failed motor is no longer possible to reanimate.
Sometimes, when a thermostat breaks down, car owners remove it without replacing it with a new one. The most popular and reliable thermostat manufacturers are Gates, Wahler and Vernet.
Conclusion
Although deviations in engine temperature from the norm can be caused by many different factors, it is the thermostat that should be checked first of all with such a malfunction. At the same time, it is not at all necessary to remove the device from the engine for express diagnostics.
