Surely every driver has seen such a situation at least once: on the highway, or on a city road, there is a car with a raised hood from under which thick steam is pouring. Such a problem is quite commonplace, and occurs in most cases due to problems with the coolant temperature sensor. In this article, we will look at the basic principles of the coolant sensor and tell you how to properly replace it yourself.
The video shows the process of replacing the coolant sensor on the VAZ-2112 in just 5 minutes:
An analogue of a foreign-made temperature sensor, the price starts from 800 rubles
In order to replace the temperature sensor, no special skills are required, you should only strictly follow the following instructions:
Before buying a new sensor, you need to make sure that the article numbers between the old and the new element are similar.
Temperature sensor malfunctions
When I see this photo, I immediately get scared. The truth is scary. The temperature arrow is far beyond the red zone, severe engine overheating
When the temperature sensor fails, it happens. In this case, steam is released into the air through all possible openings.
Please note that the antifreeze (coolant - approx.) In the system is under pressure, and in order to avoid burns, the plug of the expansion tank should be opened very carefully. By the way, and rightly so, we think so!
The temperature sensor is considered a very reliable element of the VAZ-2112 engine systems, however, it has a couple of defects that, if they occur, will require the replacement of the sensor:
- The contact in the internal components of the part has disappeared.
- Breakdowns in the insulation of the device.
The principle of operation of the sensor
This device is an ordinary resistor (thermistor - approx.), i.e. a device capable of changing its resistance depending on the temperature that surrounds it.
The sensor is mounted in a metal outlet pipe of the cooling system on the cylinder head through which the antifreeze flows.
The purpose of this sensor is to monitor the temperature of the entire cooling system, and in the event of an increase in temperature, send a pulse to start. If the sensor is faulty, then it will not give a signal in time, and.
The coolant temperature sensor (DTOZH) is the most important element of the machine, on which the timely notification of the driver about engine overheating depends. As you might guess from its name, its purpose is to measure the temperature of the coolant. It is part of the engine management system, and various engine operation parameters are regulated from its readings: ignition timing, percentage of fuel in the working mixture, crankshaft speed and many others.
The device of the coolant temperature sensor is quite commonplace. It is a thermistor placed in a housing. The thermistor is a resistor, with the characteristic that its resistance decreases with increasing temperature.
Failure of the coolant temperature sensor can lead to other problems. It is important to monitor its condition, and in case of symptoms of a malfunction, check the coolant temperature sensor and, if necessary, replace it with a new one.
What indicates a malfunction of the coolant temperature sensor
The easiest way to diagnose a problem with the coolant temperature sensor is by its appearance. In most cases, it fails due to damage, which can be mechanical or corrosive. If the sensor housing is cracked, you can forget about its stable operation. In this case, the thermistor itself, located in the housing, may also fail, and in this case the malfunction of the coolant temperature sensor will be indicated by:
- The control lamp signaling to the driver about an overheat of the engine;
- A noticeable increase in gasoline consumption;
- Problems with the motor: difficulties with starting, spontaneous stop, instability of idling and other malfunctions;
- Errors on the dashboard, determined by the electronic control unit (their numbers vary, depending on the model and manufacturer of the car).
If there are symptoms indicating a malfunction of the coolant temperature sensor, you can immediately replace it. The price of such a device is low, especially for common car models. If desired, you can diagnose it to make sure that the sensor is the source of the problems.
Where is the coolant temperature sensor
A DTOZH is a small plastic device with metal threads. With its help, it is attached to the exhaust pipe of the cylinder head, screwing into it. The sensor must be located so that it has direct contact with the coolant, on the basis of which it can be concluded that its readings are inaccurate at a low level.
Important: Some vehicle models may have two coolant temperature sensors. In this case, one of them records the temperature at the outlet of the engine, and the second at the outlet of the radiator.
Before proceeding to check the sensor itself, you need to make sure that there is no fault in the vehicle's wiring. For the DTOZH to work correctly, a voltage of 5 volts must be constantly supplied to it. Checking this is quite simple, you need to disconnect the wires from the coolant temperature sensor, and check the voltage output from them with the engine running with a voltmeter (multimeter). If no problems are found, and 5 volts are supplied to the sensor, you can start diagnosing the thermistor itself.
To check the coolant temperature sensor for the correct determination of resistance, you will need: a multimeter, a thermometer, an electric kettle (or other device that can constantly heat water), a key to dismantle the sensor.
When the tools are prepared, the first step is to remove the sensor from the car. Then you can proceed in two ways.
Method 1: Checking DTOZH in an electric kettle
The first way to diagnose the sensor is to check it using an electric kettle. For this you need:
- Place a thermometer (preferably electronic, as high temperatures will need to be measured) in a kettle of cool water;
- Next, connect a multimeter to the sensor (in the position for measuring resistance);
- Place the sensor in the teapot;
- Measure the sensor reading and write it down;
- Turn on the kettle and record the sensor resistance readings upon reaching the key heating points - +10, +15, +20 degrees Celsius and so on;
- Compare your results with the table below.
If the values obtained are very different from ideal, then the coolant temperature sensor is faulty and will need to be replaced.
Method 2: Checking DTOZH without a thermometer
A less accurate but easier way to check the sensor is without using a thermometer. Its essence lies in the fact that water, when heated, reaches 100 degrees Celsius, and its temperature cannot rise above it. Accordingly, this point can be taken as a control value, and the resistance of the sensor can be measured at a given temperature.
The full operation of the engine depends on many factors, in particular on the good condition of the parts adjacent to it. So that the engine does not overheat, it is necessary to constantly monitor the cooling system. The main function in it is performed by the engine.
The main functions of the engine cooling system
During operation, the engine reaches critical temperatures that can disable more than one mechanism in the car. To avoid such incidents, you need to remove excess heat from its parts. This function is provided by the cooling system, which also:
- Accelerates engine warm-up to operating temperature.
- Heats the air in the cabin.
- Cools exhaust gases.
- Cools the lubrication system.
There are three types of cooling system:
- Liquid - cooling occurs due to liquids (antifreeze, antifreeze, water).
- Air - cooling occurs by blowing air.
- Combined - mixed type.
Most cars, including VAZ, are equipped with a liquid cooling system using antifreeze. It includes:
- Radiator with fan.
- Furnace radiator.
- Cooling jackets.
- Water pump.
- Expansion tank.
- Connecting pipes.
- Coolant temperature sensor VAZ 2110.
The coolant passes through the system two circles:
- Small circle. This is the initial movement of the fluid, which does not yet engage the radiator. Passing a small circle, water or antifreeze provide engine warm-up.
- In a large circle, the liquid begins to flow when the engine temperature reaches one hundred degrees. The thermostat opens, and the antifreeze begins to enter the radiator, where it cools. If it does not have time to cool down with further heating, a fan comes into operation, which additionally cools both the radiator and the engine itself.
Why do we need all sorts of sensors?
The VAZ 2110 coolant temperature sensor is not the only automotive sensor. There are a huge number of all kinds of devices with which the engine control process is performed.
All sensors carry out the function of receiving information about the state of the control object. This information is then transmitted to the controller. He, in turn, plans or corrects the operation of all systems in the car.
For example, the air in the cabin is needed to control the climate inside the car. When it's cold, the stove turns on at his signal, and when it's hot, the air conditioner turns on. Thus, in addition to ensuring a comfortable stay, frosting of the windows is also prevented.
The speed sensor is needed to control the car at idle. Throttle position sensor - for the correct calculation of the fuel-air mixture. And thanks to the driver always knows how much gasoline he has left in the tank, and may not worry about not reaching the gas station.
The cost of such devices is very different - from 150 rubles to several thousand. One of the most expensive is the mass air flow sensor. The price of some of his models reaches 7000 rubles.
Coolant temperature sensor (VAZ)
This device is a semiconductor resistor with a negative temperature coefficient. It is installed in the engine cooling system on the thermostat housing. The resistance depends on the temperature. At low temperatures, the resistance is high, and vice versa.
The signals from this device are sent to the electric engine control unit. The ECU, based on the readings, corrects the supply of the fuel mixture. If the engine has not yet warmed up, an enriched mixture is supplied.
When the sensor is faulty, the ECU is given incorrect temperature readings, causing the engine to overheat and lose its functionality. Therefore, it is better not to delay the replacement of the device.
Coolant temperature sensor VAZ 2110: symptoms of malfunctions
In order for the sensor readings to be correct, it must be installed correctly, namely, next to the thermostat housing, while its tips must touch the coolant. If the readings of the device are inaccurate, the first and most significant reason may be its incorrect installation. False readings will also occur when the coolant is at a critically low level.
One way or another, sensor problems can be judged by the following signs:
- Poor quality exhaust gases.
- Increased fuel consumption.
- Deteriorated composition of exhaust gases.
- Poor engine control.
- Malfunction code or flashing of the "engine overheating" lamp.
- Difficult start.
Before "sinning" the sensor, you should check the condition of the wiring and connectors. Often, breakdowns are associated only with wires.
External diagnostics of the sensor can also indicate its non-operational state - corrosion and various deposits make it unusable. The resistance of the device is checked using a special device - a voltmeter or multimeter. The thermistor sensor shows 2 V when cold and 0.5 V when hot. Other indications indicate that it is unusable.
We change the sensor with our own hands
Despite its size and simplicity, it plays an important role in engine cooling. It happens that his testimony is inaccurate. In this case, the device should be changed.
The coolant temperature sensor is replaced in the following order:
- Drain the liquid, preferably all.
- Disconnect battery.
- For practicality, remove the air filter.
- Switch off the ignition system and disconnect the sensor connector.
- Using the key (19), you need to unscrew the sensor and remove it together with the sealing ring.
- Installation is carried out in the reverse order.
Such a device is a relatively inexpensive car spare part. A new coolant temperature sensor (2114, 2110, 2109, as well as other VAZ models) can be purchased on average for 200 rubles. The failure of this device is a common failure. Absolutely any driver will be able to cope with the replacement process. The sensor is a small but very important detail. If it starts to “jump”, it’s better not to delay the repair - it’s more expensive for yourself!
A few last words
Like it or not, the functionality of the engine depends on the smooth operation of all sensors in the system. After all, with their help, you can find out about the state of a particular part and correct its work. The VAZ 2110 coolant temperature sensor is one of the main instruments. Its malfunction can lead not only to increased fuel consumption, but also to overheating of the engine, which in the future is fraught with breakdown. And the new motor, in comparison with the sensor, is a whole financial fortune!
Taras Kaleniuk
Reading time: 4 minutes
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DTOZH performs the work of determining the thermal level of antifreeze, transmitting the collected temperature to the computer. After processing the data, the on-board computer regulates the following parameters of the engine:
- number of turns;
- saturation of the fuel mixture;
- fan operation.
The temperature sensor on the VAZ 2110 is located in the thermostat, being immersed in antifreeze. This ensures optimum accuracy of the obtained indicators.
On VAZ 2110″ width=”635″ height=”502″ /> Replacement for VAZ 2110
This vehicle has two temperature detectors. It is worth paying attention to this and, if necessary, try not to confuse them.
The one in the thermostat is the coolant temperature sensor.
The second thermal detector can be found in the cylinder head. This is a pointer sensor.
It has slightly different functions than DTOZH, but in case of any breakdowns related to the temperature of the motor, you may have to check both detectors.
The cooling system of VAZ cars is a well-coordinated work of all its parts:
- fans;
- radiators;
- sensors;
- antifreeze.
The coolant not only does the job of maintaining the temperature balance of the motor, but also protects its parts that come into contact with the medium from corrosion, and also protects the system from clogging.
And the temperature detector is designed to monitor the state of this liquid.
The same system is typical for the VAZ 2114 and similar models.
How does a temperature sensor work?
DTOZH is a device with a negative temperature coefficient, in other words, a thermistor. This means that the measured thermal data is represented by the detector in the form of resistance, which is transmitted to the control unit. The higher the heating of antifreeze, the lower the reading.
Without changing the topic, you should immediately talk about how to check the performance of the device.
To do this, you should arm yourself with a multimeter and a thermometer that can withstand high temperatures:
- to begin with, it is worth preparing a container that is filled with coolant. It is necessary to choose dishes in which it will be possible to heat the liquid;
- the multimeter is transferred to the state of an ohmmeter, a detector is connected to it;
- a sensor connected to the multimeter, as well as a thermometer, is lowered into the container with liquid
- gradual heating of antifreeze begins;
- the received data are compared with the norm and, if they do not match, then the device needs to be replaced (repair of this part is impossible, so its malfunction is treated only by purchasing a new sensor).
The exact data can be found in the documents for a specific device, but as an example, we can say that at a temperature of 30 degrees, the resistance on the multimeter will be more than one and a half thousand ohms. And as soon as the heating of the antifreeze reaches 100 degrees, the readings will drop to a level of less than two hundred.
In the same way, you can check the new temperature sensor to make sure it is working even before installation.
The data of different cars may be the same, whether it is a VAZ 2114 or a VAZ 21093, but different models of detectors may give different readings, so it is better to use the standards for this particular brand of device when checking.
How does DTOZH help the engine work?
The collected temperature data is transmitted to the control unit, which then controls the system based on the received data:
The very first thing you should pay attention to is that the engine does not start well. Regardless of the weather and temperature overboard, launching is difficult. Difficulties with stopping the engine, as well as its uncharacteristic idling, should be attributed to this symptom in one group.
The second sign is the excessive consumption of fuel and coolant. The first is due to the fact that if there is no need to supply an enriched mixture, it still saturates. And antifreeze simply boils away when the engine temperature is too high. This is especially dangerous because it can lead to engine failure.
On VAZ 2110 ″ width=”659″ height=”446″ /> To replace the temperature sensor, use a key of 19
Another reason to think about the performance of DTOZH is the uncharacteristic color of the exhaust gases, which may be a sign that the ignition angle is not working well.
With increased fuel consumption, not only the coolant temperature detector may be faulty, but also other sensors - a lambda probe, a phase sensor, etc.
Why does the engine temperature sensor break?
Actually, there aren't many of them. On VAZ 2114, 2110 or 2107 cars, the causes of failure differ little.
First of all, you should pay attention to the entire cooling system - evaluate the integrity of the wiring, the quality of the contacts and terminals, the health of the fans, as well as the level and quality of antifreeze.
All these factors can lead to the fact that the sensor fails earlier than the car owner expects (not “if”, but “when”, because any part fails sooner or later, and such a small and actively used one even more so)
Thus, before installing a new analyzer in place of a faulty one, you should make sure that the entire system is working properly so that the installed part does not burn out prematurely for the reason that the car owner was too lazy to look for breaks in the wiring.
First you need, of course, to start the engine, and then observe the temperature level scale on the dashboard.
If the arrow goes off scale and the motor is cold, you need to disconnect the contacts from the sensor and see what happens next.
For VAZ 2110″ width=”644″ height=”395″ />
If the readings have changed, then the DTOZH must be replaced. If everything remains unchanged, then the breakdown lies in the circuit to the detector - the integrity of the wiring is broken, the contacts are faulty, etc.
If the arrow twitches back and forth, you need to check the fuses.
How to replace the engine temperature sensor on a VAZ 2110?
First of all, you need to purchase a device to replace the broken one, observing the markings. In addition to official devices, there are analogues, but you need to be careful with them so as not to waste money.
Once the sensor is ready, you can start replacing:
- first of all, it is necessary to turn off the engine and cool it;
- then you need to remove the interfering parts (for example, a pipe);
- de-energize the system by removing the negative terminal from the battery;
- drain the antifreeze, since after dismantling the temperature sensor, it can spill out of the opened hole;
- disconnect the block of wires leading to the detector;
- unscrew the device with a key of a suitable size (on the VAZ 2110 this is No. 19, as on the VAZ 2114);
- put a new DTOZH in the vacant seat;
- after changing the devices, assemble the system in the reverse order and start the car to check the correct operation of the cooling system.
In order to avoid coolant leakage through the sensor socket, you can use a sealant or an o-ring.
Outcome
What is good about the domestic auto industry is that some of the nuances regarding work under the hood are almost the same for the entire model line. Take the same DTOZH. Whether it is VAZ 2108 or cars of the Samara-2 series (like VAZ 2114 or VAZ 2115), signs of malfunction, location, details of replacement are all the same.
The coolant temperature sensor is an important element in the engine management system. It is designed to control the heating of antifreeze that circulates in the cooling system. On injection VAZ-2110, the temperature sensor affects the composition of the combustible mixture, the number of revolutions of the crankshaft, as well as the ignition timing.
Sensor functions
This device performs a lot of tasks. Based on his testimony, a fuel mixture is prepared, the ignition timing changes. The element also gives commands to turn on the fan in case of overheating.
The enrichment of the mixture is always associated with elevated temperatures in the power plant. The lower the engine is heated, the richer the mixture must be fed into it. Any electronic control unit works on this principle. And the domestic ten is no exception.
Device
At the dawn of the automotive industry, simple thermal relays were used as DTOZH - they were installed on most internal combustion engines. These sensors can now be found on K-Jetronic mono-injection systems and the like. These were used on old Mercedes from the 80s and 90s. How it works? When the relay contact is in the open position, the engine warms up. When the contact is closed, the electronic control unit understands that the engine has warmed up to operating temperatures. The concentration and composition of the mixture varies.
Now thermistors are used as DTOZH. These are resistors that change resistance depending on the temperature of the environment. In a VAZ-2110 car, the coolant temperature sensor is of this type. Heating control is carried out continuously, without interruption. Thermistors for these sensors are made from nickel oxide or cobalt oxide. These alloys have a peculiarity - as the temperature rises, the number of free electrons in them increases, due to which the resistance decreases.
The thermistor inside the DTOZH has a negative temperature coefficient. The maximum level of resistance is reached when the engine is cold. The temperature sensor receives a voltage of +5 V and as the engine heats up, it decreases. The ECU detects the slightest change in voltage, and thus the coolant temperature is determined.
On engines from Renault and some other power units, sensors with positive temperature coefficients can be installed. They are set up in a similar way. However, with an increase in the temperature of the antifreeze, the resistance on the sensor does not fall, but grows.
Operating principle
The VAZ-2110 temperature sensor works as follows. The thermistor inside the sensor is an electronic device with a negative indicator of heating modes. The temperature value mode up to 130 degrees reduces the resistance within 70 Ohms, and the lower limits at -40 ° increase the resistance to 107 kOhm.
The detector supplies +5 V voltage to the temperature sensor through a fixed resistor, which is located inside it. The element determines the level of antifreeze heating due to the potential difference across the thermistor with variable resistance.
Where to find DTOZH?
Owners of vehicles of this model are well aware of the various problems associated with this device. Often the device needs to be replaced. Beginners do not always know where the temperature sensor on the VAZ-2110 is located. In cars, this element can be installed in a variety of places.
So, in classic models, the thermistor is located directly in the cylinder block. And in AvtoVAZ models of the tenth family, you can find DTOZH in the thermostat. By the way, there is more than one temperature sensor on the VAZ-2110 - there are two of them, but the second one does not perform any important tasks. It is connected only with the temperature indicator of the bottom of the instrument panel.
Typical malfunctions of the VAZ-2110 coolant temperature sensor
As you know, the ratio of fuel and air in the combustible mixture depends on the readings of the device. All owners have already encountered or will still face various problems that the temperature sensor creates. It also depends on it whether the fan will start when overheated or not.
You can suspect a malfunction of the coolant sensor on the VAZ-2110 by the following symptoms. So, the first signs are problems with starting the engine on a cold frosty morning. You can also observe poor exhaust, and fuel consumption will be significantly increased.
These symptoms do not necessarily mean that the sensor needs to be replaced. Sometimes it is enough to clean the contacts, clean the sensor itself from corrosion. If a visual inspection failed to identify problems, then you need to check the element.
DTOZH diagnostics
All car owners should know how to check the temperature sensor on the VAZ-2110. With the help of verification, you can save on the cost of a new device, although its price is not quite high.
You can test the element by heating. You need the right container. It can be a glass or a teapot. Hot water is poured into it. Water should be heated to about 100 degrees - heating should be controlled with a thermometer. Next, the working part of the device is lowered into the water. However, it is precisely that part of the temperature sensor that is located in the motor that needs to be lowered. Contacts must not be in water. Then a multimeter is connected to the contacts and the resistance is measured.
A serviceable sensor at a liquid temperature of 100 degrees has a resistance of 177 ohms. At +50 degrees, the resistance is 973 ohms. If the values do not correspond to the norm, then the defective element should be replaced. If the indicators are within these limits, then everything is in perfect order.
How to replace DTOZH
Before purchasing a new device to replace the old one, it is worth clarifying the markings on the old sensor. It is better to purchase exactly the same device.
Other, albeit similar, elements may give the wrong readings, the ECU will misunderstand them, and the driver will see false readings on the instrument panel. Complete with a new element must be a copper washer. If it is missing, it is bought separately.
Dismantling
First of all, they look at what prevents getting close to the thermostat and sensor. The air filter housing interferes - it must be removed. Next, it is recommended to drain the antifreeze from the engine, but this is not always necessary. When replacing, only a little liquid will spill, and it can always be topped up to the level.
Then, after draining the liquid, remove the terminal from the battery, select the desired sensor and remove everything that is connected to it. After detaching, the element is simply unscrewed, holding on to its edges with hands or with a key. After that, the device can be removed.
Replacing the sensor without draining the coolant
If it is decided to carry out the replacement without draining the liquid, then you need to pick up a new device, and turn the old one out a little. When the sensor can already be turned by hand, the key is removed and slowly unscrewed by hand and press the element against the hole. When it becomes clear that the device has unscrewed, it is quickly removed, and a new one is also quickly installed in its place. Then the part is twisted and its performance is checked.
Installing a new sensor
A new coolant temperature sensor on the VAZ-2110 is installed in the reverse order. Experienced motorists recommend lubricating the threads of the element with sealant.
Coolant leaks from under the new sensor are sometimes observed. The replacement process is extremely simple and even beginners who just got behind the wheel and did not know anything about cars can easily cope with it.
Air temperature sensor
Along with DTOZH, there is another element that measures the temperature in this car. This is the air temperature sensor on the VAZ-2110. It is necessary for fixing and controlling temperatures outside the car. It does not affect the preparation of the mixture or other parameters of the engine. This element is part of the so-called VAZ-2110 climate system. There is also an interior temperature sensor, which is also part of the air conditioning system.
Do not confuse these sensors with DTOZH. Although these are also thermistors, they have different functions and purposes. These elements serve only to create comfortable temperatures.
Conclusion
Everyone knows the consequences of engine overheating - these are engine parts damaged as a result of temperature deformations. The cylinder head is most often affected. Restoring this node is quite expensive. Overheating can also cause even more significant damage. When driving on a rich mixture, the engine consumes an excessive amount of fuel, candles fail. On a lean mixture, the engine heats up and can overheat. All this can be avoided if you know the signs of a DTOZH malfunction, be able to change it and know where it is located.
