The generator gets very hot, every 10 owners of VAZ and Lada cars face this problem. In fact, not only the domestic auto industry suffers from this disease, including many foreign cars that quite often have problems with generator overheating.
If the generator in your car heats up, then you should not put the problem on hold, as it is quite serious. It is better to immediately contact specialists for diagnosis and subsequent repairs.
Should the generator warm up?
Should the generator warm up at all?
The generator, like any other working unit of the car, must heat up and this is completely normal! The generator heats up mainly for three reasons. The first reason is that the generator is located next to the car engine; during operation, the engine heats up and the heat is transferred to the generator. The second reason is from voltage, if after starting the internal combustion engine you turn on the fog lights, glass blowing, high beams, etc. the generator will be loaded and it will start to heat up. The third reason is a malfunction of the generator, which is exactly what we will talk about a little later.
As you can see, in most cases it is considered quite normal for a car generator to heat up. Since its normal operating temperature is approximately 60 - 70 degrees. If the generator gets very hot, then I recommend that you immediately contact a service station.
The main reasons why the generator heats up
There can be many reasons why a generator gets very hot. Let me tell you the main ones:
- Generator malfunction: failed bearing, worn belt, etc.
- Wiring fault
- Diode bridge fault
- Accumulator battery
In any of these cases, heating the generating device will certainly lead to further problems.
The generator is getting very hot – what should I do?
The problem with a car generator is one of the most common. And why should we be surprised? The operating conditions of the generator cannot initially be called favorable. During active use, the device gets exposed to oil, dirt, salt and various substances that have harmful effects. Their effect is aggravated by high temperatures occurring in the engine compartment.
All automobile generating devices are united by their structural similarity. Regardless of the GI models, they are all susceptible to the same “diseases”, and, accordingly, methods for their “treatment”.
One of the most common problems with GU, along with increased noise and lack of charge, is its rapid heating.
It is worth a lot to be able to diagnose GI on your own. You should learn how to at least carry out initial diagnostics that would confirm the malfunction of the power unit.
- Open the hood of the car;
- First of all, start checking the alternator belt.
The belt is checked for integrity and tension. If the material shows signs of wear, large cracks and fraying, then this is a reason for replacement. A bad belt puts extra stress on the generator and other vehicle systems. Excessive load on the generator means overheating and rapid failure of the unit.
As for tension, the situation is similar here. A weak or over-tightened belt will negatively affect the operation of the generator.
The second in line after the belt is the fuse located in the block. As a rule, it is provided by the car manufacturer.
The methods described above will help determine whether the electrical connection of the unit is in order and whether the belt is intact. However, checking the device does not end there.
Here's what to do next:
- Turn on the ignition;
- Carefully monitor the battery charging indicator on the dashboard after starting the engine.
In general, if the indicator does not work when the ignition is on (half a turn of the key), then the battery may be dead, the indicator light itself may be damaged, or the wiring may be damaged. This may also indicate problems with the gene: failure of the tablet (voltage regulator), break in the winding or wear of the brushes. 
If the indicator continues to light after starting the engine, then this also indicates a problem - one or more diodes of the generating device have failed, there is a short circuit in the circuit, the pulley is faulty, etc. The indicator light should not light up, since after starting, supplying consumers with current is entrusted not to the battery, but to the generator. A glowing indicator indicates that the battery continues to power electrical appliances.
If the indicator stops lighting only after the engine speed increases, the problem is low belt tension, worn brushes or a faulty starter winding.
Further checking of the generator already implies a more detailed and professional examination. In particular, you should arm yourself with a special measuring device: a voltmeter or ohmmeter.
- The voltage is removed from the battery terminals and from the wiring going to the main unit. More than 14 volts is the standard voltage without electrical loads, 13.6 volts if optics and some other consumers are connected.
If the voltage does not exceed 12-13 volts, even after increasing engine speed to 1000 rpm, the power cable going to the power plant is in doubt.
If the readings are higher than normal, this indicates that the battery is overcharged, which a priori leads to battery failure.
Overheating of the generator is often associated with increased voltage on the vehicle's on-board network. This is usually caused by a faulty battery. A short circuit occurs inside the battery, one of the cans shorts out. This, accordingly, affects the operation of the generator.
Definitely, if the gene overheats, you should check the battery first. Often he simply sits down, for example, due to the operation of powerful acoustics. The lost supply of electrical energy requires replenishment, and what powers the battery while the engine is running is the generator. So it heats up in a short period of time if it delivers a voltage higher than it should be.
It wears out and, accordingly, the generating device heats up due to a faulty voltage regulator. A tablet or chocolate bar, as the regulator is commonly called, controls the voltage, preventing current from flowing in large quantities.
Being able to determine the cause of overheating is extremely important. In this way, it will be possible to prevent complete failure of the generating device and establish normal power supply in the network.
Why does the generator wire get hot?
Another common problem is heating of the wires coming from the generator. This problem can be dealt with very simply, since the cause will be a faulty electrical wiring.
Take the Ts-shka and ring all the wires. When you find a faulty one, simply replace it.
Why does the generator pulley get hot?
The generator pulley on a VAZ car gets hot: in this case, there can be a lot of problems, here are the main ones:
- I overtightened the belts and this caused the bearing to get hot.
- The belts are not tightened enough, they slip and heat the pulley by friction.
- Interturn.
- Short circuit in the power circuits, the rectifier may be faulty.
In any case, even if the generating device is new, disassemble it and check for the above faults. 
Why does the diode bridge of the generator get hot?
Excessive heating of the generating device will certainly lead to further problems. Heating occurs for various reasons, but most often the diodes in the unit burn out.
In general, checking the diode bridge in such cases is a must. It happens that after overhauling the generating device or replacing machine components, the car service center forgets to put gaskets on. For example, under the rectifier unit itself. Because of this, the device begins to get very hot, as it short-circuits to the case without protection (gasket).
It could also be this: the soldering on the diode bridge is relaxing. The reason will only be revealed by opening the GU (generator). There may be unsoldered contacts or so-called “dry” soldering. It is possible that the terminals are not tightened or the rectifier unit is broken.
Video: Replacing the diode bridge on the Lada Kalina
Why does the generator on the car heat up to such an extent that it is impossible to touch it? The charge is normal, no visible problems were noticed. As a rule, the gene heats up within twenty minutes of operation. What is the reason?
Is it normal for a new generator to heat up to 90-100 degrees or not? Yes, if you drive many kilometers without stopping, you won’t be able to touch the engine or other components under the hood, they will be so hot. The generating device produces currents in the region of 100-110 amperes. With such voltage and the relatively small dimensions of the power plant, as well as the lack of proper cooling, overheating is justified.
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However, strong heating after 15-20 minutes with a relatively cold engine is not the norm. It is clear that it is caused by excessive loads, and if the smell of burning is added, then the problem is obvious.
It is noteworthy that many people note a characteristic buzzing sound.
Diode bridge
Excessive heating of the generating device will certainly lead to further problems. Heating occurs for various reasons, but most often the diodes in the unit burn out.
In general, checking the diode bridge in such cases is a must. It happens that after overhauling the generating device or replacing machine components, the car service center forgets to put gaskets on. For example, under the rectifier unit itself. Because of this, the device begins to get very hot, as it short-circuits to the case without protection (gasket).
It could also be this: the soldering on the diode bridge is relaxing. The reason will only be revealed by opening the GU (generator). There may be unsoldered contacts or so-called “dry” soldering. It is possible that the terminals are not tightened or the rectifier unit is broken.
Bearings
The front or rear bearing is “covered”. This results in overheating of the GU housing, and at the same time breakdown of the winding insulation.
You can check the operation of the bearings like this. Grab the pulley and try to twist it (remove the belt first). If it’s difficult to rotate, it’s definitely a bearing problem, which is why it’s overheating.
Wiring
When it comes to overheating in the power supply system, why not pay attention to the wiring. In this case, it is recommended to test the entire positive cable laid from the battery to the power unit. It is possible that there is not enough insulation somewhere and there is a short circuit.
There should be a fuse on the wiring going from the battery to the main unit. When a diode bridge breakdown or other short circuit occurs, the fuse fails, not the positive wire. This option is available on some domestic models (for example, GAZ).
battery
In any case, the car owner should look for the reason for the high voltage consumption. That's what the experts and electricians say. And the first thing they do is diagnose the battery.
As you know, during engine operation, the PG must provide a charge to the battery. If cans or something else fly off the battery, then the current flow process will be continuous and in large quantities, which will a priori cause the device to overheat.
| Cause | Solution | |
|---|---|---|
| Battery | High voltage consumption due to excessive current output, oxidation, short circuit and failure of cans | Replace battery, charge |
| Diode bridge | Lack of gasket, loose soldering, loose terminals, breakdown | Overhaul, replacement, repair |
| Bearings | Failure of the front, rear or both together | |
| Wiring | Insufficient insulation, short circuit | Replacement of wiring, new insulation |
The problem with a car generator is one of the most common. And why should we be surprised? The operating conditions of the generator cannot initially be called favorable. During active use, the device gets exposed to oil, dirt, salt and various substances that have harmful effects. Their effect is aggravated by high temperatures occurring in the engine compartment.
Attention. Experts insist - keep the clamps of all wires of the generating device under a layer of grease. Thus, it will be possible to minimize the oxidation of the terminals at the terminals of the generating device.
Note. For example, if you leave the gene running without a connected battery, this will cause a voltage surge in the vehicle’s on-board network, which is already dangerous for various electrical devices, including the generator itself.
If the problem of generator overheating is associated with the diode bridge, then the failure of the latter is caused by just such a situation or incorrect diagnosis of the power unit.
Often, inexperienced motorists, when checking the generating device, connect the output terminal to the car body. Such a “spark” test leads to a problem, since too high a voltage flows through the diode bridge, which can damage the elements of the unit.
All automobile generating devices are united by their structural similarity. Regardless of the GI models, they are all susceptible to the same “diseases”, and, accordingly, methods for their “treatment”.
One of the most common problems with GU, along with increased noise and lack of charge, is its rapid heating.
It is worth a lot to be able to diagnose GI on your own. You should learn how to at least carry out initial diagnostics that would confirm the malfunction of the power unit.
- Open the hood of the car;
- First of all, start checking the alternator belt.
The belt is checked for integrity and tension. If the material shows signs of wear, large cracks and fraying, then this is a reason for replacement. A bad belt puts extra stress on the generator and other vehicle systems. Excessive load on the generator means overheating and rapid failure of the unit.
As for tension, the situation is similar here. A weak or over-tightened belt will negatively affect the operation of the generator.
The second in line after the belt is the fuse located in the block. As a rule, it is provided by the car manufacturer.
The methods described above will help determine whether the electrical connection of the unit is in order and whether the belt is intact. However, checking the device does not end there.
Here's what to do next:
- Turn on the ignition;
- Carefully monitor the battery charging indicator on the dashboard after starting the engine.
In general, if the indicator does not work when the ignition is on (half a turn of the key), then the battery may be dead, the indicator light itself may be damaged, or the wiring may be damaged. This may also indicate problems with the gene: failure of the tablet (voltage regulator), break in the winding or wear of the brushes.
If the indicator continues to light after starting the engine, then this also indicates a problem - one or more diodes of the generating device have failed, there is a short circuit in the circuit, the pulley is faulty, etc. The indicator light should not light up, since after starting, supplying consumers with current is entrusted not to the battery, but to the generator. A glowing indicator indicates that the battery continues to power electrical appliances.
If the indicator stops lighting only after increasing engine speed, the problem is low belt tension, worn brushes or a malfunction of the stator winding.
Further checking of the generator already implies a more detailed and professional examination. In particular, you should arm yourself with a special measuring device: a voltmeter or ohmmeter.
- The voltage is removed from the battery terminals and from the wiring going to the main unit. More than 14 volts is the standard voltage without electrical loads, 13.6 volts if optics and some other consumers are connected.
If the voltage does not exceed 12-13 volts, even after increasing engine speed to 1000 rpm, the power cable going to the power plant is in doubt.
If the readings are higher than normal, this indicates that the battery is overcharged, which a priori leads to battery failure.
Overheating of the generator is often associated with increased voltage on the vehicle's on-board network. This is usually caused by a faulty battery. A short circuit occurs inside the battery, one of the cans shorts out. This, accordingly, affects the operation of the generator.
Definitely, if the gene overheats, you should check the battery first. Often he simply sits down, for example, due to the operation of powerful acoustics. The lost supply of electrical energy requires replenishment, and what powers the battery while the engine is running is the generator. So it heats up in a short period of time if it delivers a voltage higher than it should be.
It wears out and, accordingly, the generating device heats up due to a faulty voltage regulator. A tablet or chocolate bar, as the regulator is commonly called, controls the voltage, preventing current from flowing in large quantities.
Being able to determine the cause of overheating is extremely important. In this way, it will be possible to prevent complete failure of the generating device and establish normal power supply in the network.
The engine is cold and cannot heat up. Run for a couple of minutes and the temperature rises to 80 degrees. The generator was tested for Balakirev, turned under load for 20 minutes, everything is normal.
The batteries were changed, the terminals were cleaned, but it gets hot. And the more, the less current it produces.
Who has any ideas?
As it heats up, the voltage probably drops. Due to temperature compensation. If they measured the current, they would know the load...
This is normal. There are also currents in the windings. Maybe the rotor was ground?
As it heats up, the voltage probably drops. Due to temperature compensation. If they measured the current, they would know the load...
We turn on the maximum load on the car and the current goes from seven amperes to zero. The entire load falls on the battery. There are no shorts in the wiring, sleep mode is also normal. We were the first to remove the gene, the mileage of the car is 130tkm
I'm not an expert, I just rebuilt the alternator on a Toyota, the overrunning roller jammed, it was knocking, I replaced the roller, 2 bearings that did not need to be changed. If it is not the mechanical part that is heating up, then the semiconductors are also heating up! :)) I did it on Furmanov 14, maybe they can tell me something.
I'm not an expert, I just rebuilt the alternator on a Toyota, the overrunning roller jammed, it was knocking, I replaced the roller, 2 bearings that did not need to be changed. If it is not the mechanical part that is heating up, then the semiconductors are also heating up! :)) I did it on Furmanov 14, maybe they can tell me something.
The mechanical part is normal.
Why don't semiconductors heat up when the battery is removed?
Valery Mikhalych, we found where to take him... They criticize Balakirev harshly and are not responsible for their mistakes... We take Volodya to Furmanova 14 (I’ve known him for a long time) and everything is always fine
We have been driving to Balakirev for the last two years, always without problems.
I'll take you to Furmanov.
Look at the diodes on the horseshoes. This often occurs when the polarity is not observed when connecting the battery or when lighting a cigarette from another car or starter. If the diodes are in good condition, then there may be damage to the windings during repairs and the result is interturn
Have you read the topic at least a little?
There are no shorts in the wiring
The mechanical part is normal. Why do the semiconductors not heat up when the battery is removed?
real-time data from the generator, starter and battery when starting the engine and turning on all vehicle loads.
Using current clamps, you need to check the current output in the battery while the engine is running. If the current exceeds the rated power of the generator (for example: the charging current is 70A, and the generator is 55 ampere), this will cause overheating. A faulty generator will not heat up. The problem is in the battery or in an additional source of consumption (amplifier), or change the battery, if not in it, but in the additional equipment, then you need to install a 100-amp generator. Here is an example of a heating generator with a fully charged battery, but with a closed bank.
real-time data from the generator, starter and battery when starting the engine and turning on all vehicle loads.
Is there any way to measure the internal resistance of the battery? On a fully charged one there is some small thing there. Therefore the current is zero...
