At the same time, in some cases, a problem is noted in which the engine temperature arrow jumps, the engine temperature indicator jumps when you press the gas, etc. Naturally, such deviations are the reason for the diagnosis, since the driver loses the opportunity to objectively assess the actual temperature of the power unit.
In this article we will talk about why the engine temperature arrow rises, then the pointer drops, and also for what reasons the temperature sensor power plant may give incorrect readings, the engine temperature needle floats on the move, etc.
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The engine temperature arrow jumps, floats or jumps: causes and main malfunctions
So, normally, the arrow should rise to a certain value after the internal combustion engine is fully warmed up and not deviate from its occupied position. Note that while driving, small deviations are quite allowed, and often in a smaller direction.
Usually this phenomenon is observed in the cold season, often when driving on the highway. This is due to the fact that in cold weather the engine is intensively cooled at high speed by oncoming flows of cold air.
Also, part of the heat from the motor in winter period takes the stove. As a result, the arrow may “fall” a little (by 2-3 mm from normal values). If you reduce the speed of movement or allow the car to work for several minutes at idle, then the temperature gauge will rise to a normal value.
If we talk about problems, there should not be any obvious jumps in the temperature gauge. In cases where the arrow of the temperature gauge floats, in the presence of a digital indication, the “sticks” of temperature are constantly changing, then this is the main symptom of various problems. Let's figure it out.
- First, in order to understand why the arrow of the engine temperature gauge is jumping, it should be borne in mind that changing readings on the indicator do not always mean that in reality such significant changes in internal combustion engine temperature occur.
In other words, a change in readings in the average range of 75-95 degrees does not reflect the real picture, since the heated coolant () cannot heat up and cool down so quickly. It turns out that the pointer does not display the actual temperature of the motor.
If otherwise, a smooth change in readings can be taken as the norm, moreover, making an allowance for the conditional error of the pointer or digital indicator itself. Moreover, if the temperature fluctuations do not go beyond the permissible limits, it is likely that this is the operating temperature of the engine.
The cause for concern is the chaotic, usually sharp fluctuations of the needle, and the amplitude of such fluctuations is quite large. In this situation, it is necessary to determine whether a violation of the thermal balance really occurs, whether the indicator itself is working normally, and also for what reasons the malfunction occurred.
- So let's go. If the system is sealed and the coolant level is normal, then the most frequently failing element, on which the engine temperature directly depends, is. Moreover, this device often fails even on completely new cars with minimal mileage. So it is better to start checking with the thermostat.
The simplest way of primary diagnosis is to assess the degree of heating of the inlet pipes leading to the radiator. It is enough to touch the nozzles with your hand. If the bottom outlet is colder than the top, it is likely that the thermostat valve is stuck. As a result, even on a cold internal combustion engine, the coolant enters a large circle, and the engine cannot reach operating temperatures.
In practice, this manifests itself as follows, when the driver first warms up the engine, the temperature arrow rises to operating temperatures, then the thermostat opens. Further, the coolant goes in a big circle, the temperature of the motor decreases, but then the thermostat wedges and does not close completely.
Naturally, the liquid continues to partially or completely go through the radiator (in a large circle). As a result, the engine starts to cool down, the temperature needle drops. Then the thermostat will either close, after which the coolant will heat up to operating temperatures, or it will remain in a jammed position and the engine will not warm up to the end.
In this case, often after stopping the engine and dropping pressure in the cooling system, then the arrow will first rise to normal temperatures as it warms up, but then after the thermostat opens, everything will repeat again. There are also cases when the thermostat may not wedge constantly, but every other time, and also not open access for the coolant to a large circle.
In this case, the engine will overheat. It happens that the operation of the thermostat is disrupted both for opening and closing, that is, it is appropriate to talk about a set of problems. Anyway, .
- Now let's look at the situation when the engine temperature needle jumps, but everything is in order with the thermostat and other elements of the cooling system. In this case, the problem may be in the coolant temperature sensor (DTOZH). It turns out that if the temperature arrow jumps, the culprit is often an incorrect signal from the temperature sensor.
This means that you need to check the specified sensor. At the same time, it is important to consider that on many cars there can be 2, 3 or even 4 such sensors. These sensors are also located in different places, depending on the design of a particular internal combustion engine.
Also, a separate sensor sends a signal to the instrument panel so that its readings in the event of a failure do not make changes to the operation of the engine. Having found the desired temperature sensor, you need to check its contact. It is enough to move the sensor or the terminal-chip on it.
At this time, the assistant must monitor whether the temperature indicator fluctuates on the instrument panel in the passenger compartment. Often, poor contact causes the temperature arrow to jump, while the cooling system is working normally.
If the matter is not in contact, the sensor itself may be out of order. To check this, you should measure the resistance at different coolant temperatures. To do this, you need to know what resistance is considered normal for a sensor on one or another internal combustion engine under certain conditions.
This information can be found in specialized forums, technical literature, etc. We also note that one should not immediately hastily and unequivocally attribute all problems to the thermostat without checking the temperature sensors. The arrow can jump and jump if the contact points on the sensor are simply oxidized, the connection is loosened. Moreover, jumps can occur only when powerful energy consumers are turned on (heated seats, windows, headlights, etc.).
We also add that in the event of a malfunction of the sensor itself, the readings usually change in a certain range. If they change randomly, then most likely there are problems with the wiring. Often the negative contact becomes the culprit.
There have been cases when, with problems with the "mass", the temperature gauge showed critical overheating, and after the engine stopped, the normal 90 degrees. At the same time, the measurements at the terminals with the engine turned off were about 12.5, after starting they rose to 13.7 V.
At the same time, neither the replacement of the battery with temperature sensors, nor the diagnostics and testing solved the problem. The way out of this situation was additional.
The temperature needle jumps with a working thermostat and DTOZH
In some cases, it happens that the thermostat is working, as well as the temperature sensor and wiring. At the same time, the temperature arrow jumps arbitrarily, overestimating or underestimating the readings, in an arbitrary range.
Often the problem lies in the electronic board of the instrument panel. If the soldering of such a board is of poor quality, problems arise after a few years. You can fix the problem by disassembling the shield and soldering. As part of such work, special attention should be paid to resistors and output mass. If you plan to do the work yourself, you need to have a low power soldering iron with a thin rod.
We also note that the arrow, with other serviceable elements, both mechanically and electrically, can jump if the engine cooling system is airy. In other words, the air in the cooling system forms airlock. Such a cork heats up much faster and more strongly than antifreeze or antifreeze.
As a result, the sensor responds to temperature changes, the pointer arrow randomly changes position. At the same time, the air in the system is indirectly indicated by the fact that the liquid is leaking from under the cover expansion tank, there may be a noticeable decrease in the level in the tank, etc.
What is the result
As you can see, there are not so many reasons for the arrow of the engine temperature gauge on the dashboard to start jumping or jumping. However, within the framework of diagnostics, an integrated approach should still be used, excluding possible problems one by one.
As a rule, you should start by checking the contacts of the sensor and the ground, then the temperature sensor itself is checked with a multimeter, after which the thermostat is diagnosed. If all the elements are working, then the problem may be in the instrument panel itself.
Finally, we note, the main thing is to make sure that the engine really does not experience overheating or completely reaches operating temperatures. To check this, you can. This approach will narrow the range of potentially problematic elements and quickly find the problem.
Read also
How to understand that the engine has begun to overheat: obvious and hidden signs of overheating of the motor. Common reasons for overheating.
Many motorists were faced with the fact that the arrow of the temperature gauge on the VAZ-2114 instrument panel went up, beyond the red zone. This malfunction may be due to many factors. But, this problem is related to the electrical part of the car.
Why the temperature arrow goes off scale - the main reasons!
You can find out why the malfunction occurred in your garage, and it is not necessary to go to a car service. But to fix the problem, you may need outside help professionals.
So, let's consider the main reasons that the temperature arrow on the VAZ-2114 dashboard goes up:
- Dashboard diagram.
- Temperature sensor.
- Wiring harness.
Solution Methods
The arrow goes off the scale!
When the causes are identified, you can go directly to their elimination, and consider the issue in more detail. So, for starters, it is worth noting that the motorist will need some knowledge design features car, as well as knowledge in the electrical part.
Dashboard diagram
dashboard board
The first place to look for a problem is the dashboard. In order to fix the malfunction, you will have to dismantle the “tidy”, as well as disassemble it.
The next step will be that you need to find a motor, which just drives the arrow. There may be two faults here. Which ones exactly:
- Due to a short circuit, the motor winding burned out.
- The wire that is soldered from the motor to the dashboard board is soldered or torn off.
To eliminate this cause, it is necessary to inspect the place and determine the presence of cliffs. For complete reliability, it is necessary to ring the contact wires of the motor, which close the winding.
Another diagnostic step will be the connector that connects to the board. It is necessary to find a contact that is responsible for the temperature indicator and also ring it with a multimeter. If a connection break is detected, then it must be eliminated.
Attention! If the motorist does not have experience in repairing such components, it is strongly recommended to contact professional auto electricians in order to self repair not cause more trouble. They will do everything quickly and efficiently.
temperature sensor
The temperature sensor is checked with a multimeter
If the problem was not hidden in the dashboard, then you need to contact directly temperature sensor . It is he who serves as an indicator of engine temperature and transmits data through the computer to the arrow. The failure of the product can cause the effect of hanging, and the arrow on the dashboard going off scale.
To determine the operability of the sensor, it must be dismantled and “ringed” using a multimeter. If it is found to be "dead", .
wiring harness
Disconnecting the wiring harness from the dashboard for inspection
If the first two causes are eliminated, but the problem remains, then it is worth looking for a problem in the wiring harness that goes from the engine to the dashboard. Of course, not all motorists are able to cope with this type of diagnosis, due to ignorance of the pinout of the wires. Therefore, in this case, it is also worth contacting professional auto electricians to find out the causes and repair. Although, the reason here is quite simple and understandable - a wire break or burnout.
ECU
List of ECU errors
Not often the problem of leaving the arrow from the normal position can be provoked by the electronic control unit. It is he who sets all the parameters and signals on the dashboard.
To fix the problem, you need to connect to it and check for errors associated with the temperature sensor and the cooling system. So, an elementary reset of errors can lead to the normalization of the device.
conclusions
There are not many reasons for the VAZ-2114 engine temperature arrow to go off scale, but all of them are quite difficult to diagnose, and some are eliminated only in a car service. Therefore, if the motorist did not carry out repair operations of this nature, it is necessary to contact a car service center, where they will help and repair everything.
Haven't looked at the engine temperature indicator right in front of your eyes for a long time? It means that you are lucky, the arrow stands as if rooted to the spot, and you simply do not pay attention to it. But not everyone is so lucky.
Some drivers complain that the needle floats like a windshield wiper blade, and when the bar indication changes, the sticks change like on an equalizer bar. How can this be explained? The article attempts to systematize such phenomena, and proposes measures to eliminate them.
Is the thermostat to blame
Forum members often ask: why does the arrow of the engine temperature gauge jump? Before answering, it is necessary to clarify the very formulation of the question. Changing gauge readings do not necessarily mean that the engine temperature is jumping.
For example, the arrow oscillates in a sector from 70 to 90 degrees or fluctuates randomly with a large amplitude. But after all, the heated coolant (coolant) has thermal inertia, and cannot change its parameters so sharply. It follows that the readings of the device may not reflect the actual temperature of the engine. internal combustion(ICE).
If the readings change rather slowly, we can assume that they show the actual degree of heating of the motor. In this case, it is necessary to critically assess the situation: are temperature fluctuations really dangerous? When they occur between 90 and 105°C there is no cause for alarm as this is the normal operating temperature that the thermostat maintains.
Now, if smooth fluctuations go beyond this range, then you should look for the reasons for the violation of the thermal balance. Maybe the thermostat is the culprit. But this still needs to be verified.
The easiest way is to try heating the inlet pipes to the radiator by touch. Suspicion is confirmed when the lower pipe is slightly colder than the upper one. This means that the thermostat control valve is sticking open and the engine is running undercooled. A similar thermostat malfunction is usually encountered by 70 thousand kilometers.
Or maybe it's the sensor?
When the temperature needle moves, it only follows the changing signal that comes from the temperature sensor. It follows that if the latter is lying, then the pointer also shows incorrect information. Therefore, when the pointer on the dashboard starts to misbehave, making sudden movements, you must first check the sensor.
Attention: on modern internal combustion engines, from 2 to 4 temperature sensors are installed. Their installation locations different cars may differ.
Usually a separate sensor goes to the shield so that it does not introduce an error into the work electronic system control (ECU). After it is found, you should make sure that there is a contact on the connecting terminal. Shake it slightly, and let a friend follow the behavior of the arrow. Sometimes the reason is extremely simple - a loose connection or an oily terminal.
If the contact is normal, you should check the performance of the sensor itself. To do this, use a portable ohmmeter, which measures the resistance of the element under test at different temperatures. These values are taken from the table contained in the product documentation.
As an example, a few lines from the passport data of the coolant temperature sensor (DTOZH) 23.3828
Sometimes the driver is so obsessed with the alleged malfunction of the thermostat that he long and hard seeks to replace it under warranty. When his efforts reach their goal, it turns out that everything remains the same. And only after replacing the temperature sensors, the operation of the indicator returns to normal.
Have a contact
As electricians say, there can be only two faults: there is no contact where it is needed, or there is, where it is not needed. This rule also applies in this situation. The arrow will jump if the joints are oxidized or weakened. And most often this happens when additional consumers are connected: dipped beam, dimensions, etc.
As mentioned above, the first thing to do when diagnosing DTOZH is to check the contact in the connector. Returning to the previous section, the following should be added: if the sensor malfunctions, the readings jump in the same range, and if they change randomly, the wiring may also be damaged. How important is the negative contact - the mass, will confirm one case described by a forum member.
The pointer sometimes jumped up to 130°C. After stopping the engine, it showed the correct result - 90 °. The voltage at the battery terminals with the engine off was about 12.5 V, and after starting it rose to 13.7.
After a year and a half of unsuccessful searches for the cause, replacing the battery, generator and two temperature sensors, one grandpa got caught, who installed an additional mass wire from the motor to the body, and the problem was solved.
Soldering iron in your hands
Do not forget that the thermostat, and the DTOZH, and the wiring may be serviceable, but the temperature gauge still works abnormally, and its behavior is unpredictable. Here, most likely, the electronic instrument panel board (“brains”) is the culprit. This node has a lot of complaints from drivers.
The fact is that the component base, obviously, is not soldered very well. After a few years of operation, the soldering points oxidize, and the control unit begins to “fail”. The best solution is to dismantle dashboard and careful soldering of all elements.
Particular attention should be paid to the soldering of the resistors and the output mass. Along the way, acquire radio engineering skills. The soldering iron should have a thin tip and low power. Of course, opening the front panel is not an easy task, and you need to resort to such repairs as a last resort.
Attention - air
Finally, one more possible reason sharp movements of the arrow, - the presence of air bubbles in the antifreeze ("airing" of the system). Since the air and antifreeze have different temperatures, the arrow jerks. Indirect sign this malfunction is the splashing of coolant from the radiator cap or expansion tank, as well as a decrease in the filling volume.
Summing up, we can suggest the following procedure for checking the elements: contacts, ground, temperature sensor (DTOZH), thermostat, indicator board. Renault Logan owners should not dramatize the 2-4-2 indication. This is the normal operating mode of the thermostat.
P.S. In order not to upset the logan drivers, on the Duster and the second generation Logan-Sandero, the temperature gauge on the dashboard was removed altogether. As they say: no pointer - no problem.
