In this case, in some cases, a problem is noted in which the engine temperature arrow jumps, the engine temperature indicator jumps when the gas is pressed, etc. Naturally, such deviations are a reason for diagnostics, since the driver loses the ability to objectively assess the real temperature of the power unit.
In this article we will talk about why the engine temperature needle rises, then the pointer goes down, and also for what reasons the power plant temperature sensor may give incorrect readings, the engine temperature arrow 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 has completely warmed up and not deviate from the 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 counter currents of cold air.
Also, part of the heat from the engine in winter is taken away by the stove. As a result, the arrow may "fall" a little (by 2-3 mm from the usual values). If you slow down or let the car run for a few minutes at XX, then the temperature gauge will rise to its normal value.
If we talk about malfunctions, there should be no obvious jumps in the temperature gauge. In cases where the arrow of the temperature indicator floats, in the presence of a digital indication of the "stick", the temperatures are constantly changing, then this serves as the main symptom of various malfunctions. 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 such significant changes in the temperature of the internal combustion engine occur in reality.
In other words, the change in readings in the average range of 75-95 degrees does not reflect the actual picture, since the heated coolant () cannot heat up and cool down so quickly. It turns out that the pointer does not display the real temperature of the motor.
Otherwise, a smooth change in readings can be taken as the norm, and making a correction for the conditional error of the pointer or digital indicator itself. Moreover, if temperature fluctuations are within acceptable limits, it is likely that this is the operating temperature of the engine.
Chaotic, usually sharp fluctuations of the arrow are a cause for concern, and the amplitude of such fluctuations is quite large. In this situation, it is necessary to determine whether there is really a violation of the thermal balance, whether the indicator itself works normally, and also for what reasons the malfunction has 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 the test with the thermostat.
The simplest way of primary diagnostics is to assess the degree of heating of the supply pipes going to the radiator. It is enough to touch the pipes with your hand. If the lower pipe is lower than the upper pipe, 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 first the driver warms up the engine, the temperature arrow rises to operating temperatures, then the thermostat opens. Further, the coolant goes in a large circle, the engine temperature decreases, but then the thermostat wedges and does not close completely.
Naturally, the liquid continues to flow partially or completely through the radiator (in a large circle). As a result, the engine begins to cool down, the temperature arrow 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 fully warm up.
In this case, often after stopping the engine and a drop in pressure in the cooling system, the arrow will first rise to normal temperatures as it warms up, but then after opening the thermostat, everything will be repeated again. There are also cases when the thermostat may not wedge all the time, but every other time, and also not open access to the coolant in a large circle.
In this case, the engine will overheat. It so 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 arrow 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. It is important to take into account that many cars have 2, 3 or even 4 such sensors. These sensors also stand 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 change 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 chip terminal on it.
At this time, the assistant must monitor whether the temperature indicator on the instrument panel in the car's interior fluctuates. 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 the other ICE in certain conditions.
This information can be found in specialized forums, in technical literature, etc. Also note that you should not immediately and unambiguously blame all the problems on 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 loose. 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 within a certain range. If they change chaotically, then most likely problems have arisen with the wiring. Often the negative contact becomes the culprit.
There have been cases when, in case of problems with the "mass", the temperature gauge showed critical overheating, and after stopping the motor, normal 90 degrees. In this case, the measurements at the terminals with the motor turned off were about 12.5, after starting they rose to 13.7 V.
At the same time, neither replacement of the battery with temperature sensors, nor diagnostics and testing of the problem solved the problem. There was an additional way out of this situation.
The temperature arrow jumps with the operating thermostat and DTOZH
In some cases, it happens that the thermostat is working, as well as the temperature sensor and wiring. In this case, 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 turns out to be of poor quality, problems arise after several years. You can eliminate the malfunction by disassembling the shield and soldering. Within the framework 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 in mechanical and electrical parts, can jump if the engine cooling system is airy. In other words, the air in the cooling system forms an air lock. Such a plug heats up much faster and more strongly than antifreeze or antifreeze.
As a result, the sensor reacts to temperature changes, the pointer arrow randomly changes position. At the same time, the air in the system indirectly indicates that the liquid is leaking from under the cover of the 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, you should still apply an integrated approach, excluding possible problems one by one.
As a rule, you should start by checking the contacts of the sensor and 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, to make sure that the engine really does not experience overheating or completely reaches operating temperatures. To check this, you can. This approach will allow you to narrow the range of potentially problematic elements and quickly find a malfunction.
Read also
How to understand that the engine has started to overheat: obvious and hidden signs of engine overheating. Common causes of overheating.
Many motorists were faced with the fact that the arrow of the temperature gauge on the instrument panel of the VAZ-2114 went up, beyond the aisles of the red zone. This malfunction can be associated with 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 also find out what caused the malfunction in your garage, and it is not necessary to go to a car service. But to fix the problem, you may need third-party help from professionals.
So, let's consider the main reasons that the temperature arrow on the VAZ-2114 dashboard goes up:
- Dashboard diagram.
- Temperature sensor.
- Wire harness.
Solution methods
The arrow goes off scale!
When the reasons are identified, you can go directly to their elimination, and consider the issue in more detail. So, to begin with, it is worth noting that the motorist will need some knowledge of the design features of the car, as well as knowledge of the electrical part.
Dashboard diagram
Dashboard board
The first place to look for a problem is the dashboard. In order to eliminate 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 that just drives the arrow. There can be two faults here. Which ones:
- Due to a short circuit, the motor winding burned out.
- The wire that is soldered from the motor to the dashboard board is unsoldered or torn off.
To eliminate this cause, it is necessary to inspect the place and determine the presence of breaks. 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 break in communication is detected, then it is necessary to eliminate it.
Attention! If a motorist does not have experience in repairing such units, it is strongly recommended to contact a professional auto electrician so that he does not make even more trouble during self-repair. 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 must contact directly temperature sensor ... It is he who serves as an indicator of the engine temperature and transmits data through the ECU to the arrow. Failure of the product can cause the effect of freezing, and off-scale arrows on the dashboard.
To determine the sensor's performance, it must be dismantled and “ringing” with a multimeter. If it is determined that it is "dead",.
Wire harness
Disconnecting the wiring harness from the dashboard for inspection
If the first two causes are eliminated, but the problem persists, then you should look for the 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 reasons and repair. Although, the reason here is quite simple and clear - wire breakage or burnout.
ECU
ECU error list
Not often, the problem of the arrow leaving the normal position can be provoked by the electronic control unit. It is he who sets all the parameters and signals to the dashboard.
To fix the problem, you need to connect to it and check for errors connected to 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 overscale of the VAZ-2114 engine temperature arrow, but they are all quite difficult to diagnose, and some are eliminated only in a car service. Therefore, if the motorist has not carried out repair operations of a similar nature, it is necessary to contact a car service, where they will help and repair everything.
Haven't you looked at the engine temperature gauge right in front of your eyes for a long time? So, you are in luck, the arrow stands 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 wiper blade, and when the bar display, the sticks change, like on an equalizer scale. How can this be explained? The article makes an attempt to systematize such phenomena, and proposes measures to eliminate them.
Is the thermostat to blame
Forum participants often ask: why does the arrow of the engine temperature gauge jump? Before answering, you should clarify the very formulation of the question. Changing gauge readings do not necessarily mean that the engine temperature is jumping.
For example, an arrow swings in a sector from 70 to 90 degrees or fluctuates chaotically with a large amplitude. But the heated coolant (coolant) has thermal inertia and cannot change its parameters so dramatically. Hence it follows that the readings of the device may not reflect the real temperature of the internal combustion engine (ICE).
If the reading changes rather slowly, it can be assumed to indicate 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 maintained by the thermostat.
Now, if smooth fluctuations go beyond this range, then you should look for the reasons for the violation of the thermal balance. The thermostat may be the culprit. But this still needs to be verified.
The easiest way is to feel the heating of the supply pipes to the radiator by touch. The suspicion is confirmed when the lower branch pipe is slightly colder than the upper one. This means that the thermostat control valve wedges open and the engine runs underheated. A similar malfunction of the thermostat is usually encountered up to 70 thousand kilometers.
Or maybe it's the sensor?
When the temperature arrow walks, it just 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 begins to misbehave, making sudden movements, you must first check the sensor.
Attention: modern internal combustion engines are equipped with 2 to 4 temperature sensors. The places of their installation on different cars may differ.
Usually, there is a separate sensor on the shield so that it does not introduce an error in the operation of the electronic control system (ECU). After finding it, you should make sure that there is a contact on the connecting terminal. Shake it slightly, and let a friend follow the arrow's behavior. Sometimes the reason is extremely simple - a loose connection or an oily terminal.
If the contact is normal, 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 \u200b\u200bare 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 fixated on the alleged malfunction of the thermostat that he long and persistently seeks its replacement under warranty. When his efforts reach the goal, it turns out that everything remains the same. And only after replacing the temperature sensors, the operation of the pointer returns to normal.
Contact
As electricians say, there can be only two malfunctions: there is no contact where it is needed, or there is where it is not needed. This rule also applies in the situation under consideration. The arrow will jump if the joints are oxidized or weakened. Moreover, most often this happens when additional consumers are connected: dipped beam, dimensions, etc.
As mentioned above, the first thing to do when diagnosing a DTOZH is to check the contact in the connector. Returning to the previous section, the following should be added: if the sensor is faulty, the readings jump in the same range, and if they change chaotically, damage to the wiring is possible. How important is the negative contact - mass, will be confirmed by one case described by a forum member.
The pointer arrow sometimes jumped up to 130 ° C. After stopping the engine, it showed the correct result - 90 °. The voltage at the battery terminals when the engine was not running 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 came across, who installed an additional mass wire from the engine to the body, and the problem was solved.
Soldering iron in your hands
Do not forget that the thermostat, and DTOZh, and the wiring can be serviceable, and the temperature indicator still works abnormally, and its behavior is unpredictable. Here, most likely, the culprit is the electronic board of the instrument panel ("brains"). This site has a lot of complaints from drivers.
The fact is that the component base is obviously not soldered too well. After several years of operation, the soldering points are oxidized, and the control unit begins to "glitch". The best way out is to dismantle the instrument panel and thoroughly solder all elements.
Particular attention should be paid to the soldering of the resistors and the output ground. Along the way, you will 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 last.
Attention - air
Finally, another possible reason for the sharp movements of the arrow is the presence of air bubbles in the antifreeze ("airing" the system). Since air and antifreeze have different temperatures, the arrow jerks. An indirect sign of this malfunction is the coolant splashing out of 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, pointer 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 loganovods, on the Duster and the second generation of the Logan-Sandero, the temperature indicator on the dashboard was completely removed. As the saying goes: no pointer - no problem.
