An alternator belt or an accessory belt drives a number of devices: a car generator, power steering pump, air conditioning compressor, etc. It is important that the specified belt is tensioned correctly.
If the attachment belt is overtightened or loose, then:
- the generator may not work correctly (the battery does not charge, the voltage drops);
- the generator belt whistles;
- bearings and pulleys of attachments wear out;
- The belt itself becomes unusable faster, etc.
To avoid such problems, the alternator belt must be changed in a timely manner, as well as correctly tensioned during installation and monitor the tension during vehicle operation. If necessary, adjust the belt tension. Read more in our article.
The importance of belt tension and checking it
Any deviation from the recommended tension force is unacceptable. When the force weakens, the belt begins to slip.
This is not determined visually, but the generator rotor speed drops, reducing the generated voltage.
The consequence of this is systematic undercharging of the battery.
Power decreases, the starter turns hard, and in winter you may not be able to start the car at all. Undercharging affects the battery life, reducing it.
The load on the electrical system increases, and some devices may fail. Due to slippage, the belt overheats and quickly fails due to heat and increased abrasion.
Checking belt tension.
Excessive tension is even worse. In this case, the belt is also subject to increased wear and tear, and often breaks.
Much worse is that the load on the crankshaft and generator bearings increases sharply.
If you drive for a long time with a tightened belt, there is a high probability that you will have to repair the generator or the engine itself.
You can increase the tension only in one case - if on the road it turns out that the belt has stretched or worn out and began to slip.
But in this mode you can only get to the place where it is possible to change the belt for a new one. At the same time, you should not exceed the speed of 60-70 km/h.
What happens if you drag
Not all motorists know what will happen if drivers overtighten the belt during tensioning. Increased load increases wear on the unit. It manifests itself in the form of a characteristic hum from an electrical appliance. The main noise comes from bearings and rollers, which will create increased tension. Due to pinching, it will be more expensive to repair the water pump or air conditioning compressor involved in the circuit. It is worth paying attention to the special marks used by manufacturers to monitor tensioner wear and timely replacement of the belt.
Checking the tension of the generator belt
The recommended tension values vary for different car models. They depend on the machine itself, the brand of alternator and belt used.
It is also important whether there are additional equipment that is also driven by the belt: air conditioning, power steering.
Typically, to check the tension force, you need to press on the longest section of the belt with your hand with a force of about 10 kg.
The deviation from the normal position should be approximately 10 mm.
For example, on a VAZ 2115 this value is 10-15 mm for a generator type 37.3701 and 6-10 mm for 9402.3701.
If the check shows that the belt deflection is more or less than expected, it must be brought to the proper value.
Depending on the vehicle, one of 3 methods can be used, which are described below.
Attention! Often, a whistling sound indicates that the generator tension is weakened. The battery charging light may also go out, although not always. Sometimes it blinks. If such symptoms occur, the first thing you need to do is check the tension. If it is in order, you will need to check the health of the generator itself and the electrical system.
Signs and consequences of the problem
The belt is the weak link of any transmission. Constantly rotating between the pulleys and transmitting torque, the element gradually wears out and its tension begins to weaken. Over time, slippage and accelerated abrasion of the rubber product occurs, leading to its breakage. Engine oil or coolant (or both) that has gotten onto the working surface can loosen the belt prematurely.
Reference. In different brands of passenger cars, 3 types of alternator belts are used - standard V-shaped, multi-ribbed and toothed.
When it is necessary to check and tighten the belt drive:
- It is worth checking the belt at every opportunity when you open the hood of the car. On the vast majority of machines this will not be difficult - just reach out and press on top of the rubber product.
- If when the engine is running, especially after pressing the accelerator pedal, a loud, unpleasant squeak is heard from under the hood. The sound clearly indicates the belt drive is slipping on the pulleys.
- You should check the tension of the alternator belt when the red battery charging indicator on the dashboard periodically lights up.
- After disassembling and repairing the power unit, which involves removing this unit.
Slipping or breaking the belt does not have fatal consequences, but significantly reduces the battery life. When the generator shaft rotates intermittently or does not rotate at all, the on-board network receives voltage from the battery. Since decent power is needed to spark and power the systems, it discharges to zero quite quickly. Restoring the charge of a completely dead acid battery is quite difficult, and often impossible.
Tensioning the alternator belt using the adjusting bar
The method is used on older machines. In particular, on old model Zhiguli cars.
The generator is attached at 2 points: with a bolt to the housing eye and with the help of a sector strip with a slot into which a bolt is inserted and screwed into the generator housing.
By loosening the bolts, the assembly can be moved relative to the bar, increasing or loosening the tension, after which the bolts are tightened again.
Tensioning the generator using a bar.
The general adjustment algorithm is performed as follows:
- Loosen the bolt on the bar and on the eye.
- We move the generator to the optimal position; this cannot be done by hand; you need to use a pry bar.
- First tighten the bolt on the bar, then on the eye.
The work is not difficult, but the adjustment is not the most convenient due to the need to use a pry bar.
Tightening instructions
To tighten the alternator belt on most passenger cars, you will need literally 2 open-end or ring wrenches plus a mounting spade. First remove the plastic casing and other elements blocking free access to the unit. For the sake of convenience, give the warmed-up engine half an hour to cool down and put on cloth gloves.
It is better to tension the belt of front-wheel drive VAZ cars and imported cars of similar design in an inspection ditch. It makes it easier to get to the generator mounting bolt. If there is no hole, you will have to remove the right front wheel or lie on the ground under the car.
The lift is performed in the following order:
- Secure the machine with the handbrake and set it to first speed so that the crankshaft pulley does not turn while working.
- If access to the lower bolt of the generator is blocked by the oil pan protection, then this casing will have to be removed.
- Next, you need to loosen the nut on the bolt of the lower bracket securing the generator. Unscrew it 2-3 turns.
- Loosen the second nut on the upper adjustment bracket (operation is performed from the hood side).
- With the mounting blade resting on the generator housing, carefully move the unit further away from the crankshaft and immediately tighten the nut on the bracket.
- If the vehicle is designed with a tension bolt, a spade will not be needed. Tightening this bolt tightens the belt, unscrewing it loosens it.
Before finally tightening the lower fastener, check the drive belt tension. If you overdid it and the element is too tight, you need to loosen the top nut again and adjust the position of the generator.
Advice. Pay attention to the condition of the belt - whether cracks have formed or threads have crawled along the sides. If you find signs of critical wear, hurry up to buy a spare element and put it in the trunk, or better yet, change it right away.
Tensioning the alternator belt, which rotates 3-4 pulleys simultaneously, depends on the specific brand of machine. For example, in Chevrolet Niva cars the generator does not unscrew at all, since the design provides for a tension roller mounted on a plate. First, the fastening of this plate is loosened, then the tension bolt is tightened. Since the roller is located in a narrow opening between the radiator and the engine, you will need a short socket wrench with a crank to unscrew it.
Tensioning the alternator belt using an adjusting bolt
The method is widely used on modern car models. It is more convenient than the previous one, because a mount is not needed, and the tension force adjustment is more accurate.
Tensioning the generator using an adjusting bolt.
The generator is moved using an adjusting bolt, which is turned with a wrench.
The setup process goes like this:
- The bolts securing the assembly at the top and bottom are loosened.
- Using a wrench, we change the position of the generator, achieving a change in belt tension.
- We tighten the bolts back, fixing the position of the generator.
The convenience of this method is that the degree of tension can be checked directly during adjustment. For the arcuate bar method, verification is possible only after fixing the generator.
Let's sum it up
To avoid any problems in the operation of the generator, it is necessary to correctly configure the operation of the belt and other components. In this case, you can get good operation of the car's electrical system, avoid excessive tension or insufficient tension of the belt and guarantee its high-quality and long-term operation. Otherwise, you will have to come to terms with the need for constant repairs and regular correction of problems with the tension of the alternator belt.
If the procedure turns out to be quite complicated, it is better to turn to professionals - the alternator belt tensioning service will not cost too much. Your vehicle may have a specific design for adjusting the belt. And in this case, it is also better to entrust the work to specialists. Have you ever had to adjust the tension of the alternator belt yourself or install the belt in emergency conditions?
Adjusting the tension of the generator belt using a roller
In a number of modern car models, a special adjusting roller is responsible for belt tension.
The adjustment in this case is quite simple and convenient, but requires the use of a special key.
A similar tensioning method is used on the Lada Priora; this car is one of the most popular and widespread in our country, so let’s look at the process using its example.
Tension the generator using an adjusting roller.
Video “Example of tension on a VAZ 2110”
The In the Garage channel presented detailed instructions on how to carry out the process of tightening the generator drive belt using the “tens” as an example.
The article describes in great detail why the generator drive is tensioned and why it should not be tightened or loosened too much. A step-by-step procedure for replacing the belt and adjusting it is also provided.
How to tighten the alternator belt on a Priora
The tension roller is part of the Priora engine design. To carry out the work, you will need a 17-mm open-end wrench and a special key for turning the roller.
It is a lever, at one end of which 2 small rods with a cross-section of 4 mm are welded, spaced 18 mm from each other.
The rods are inserted into the corresponding holes on the roller body. By pressing the key, the roller moves along its axis.
The fact is that the roller has an oval design, so when moving along the axis, it tightens or loosens the belt depending on which side it is turned.
A special wrench is a common tool; you can buy it inexpensively at almost any auto parts store.
You can also spin the roller using pliers with narrow curved jaws, but this is not so convenient. In addition, when working with pliers, they can slip , which will damage your hand.
Use a wrench to unscrew the 17-head bolt that secures the roller. Then, by inserting a special key into the holes, the roller rotates, loosening or increasing the belt tension. The procedure is very simple.
Procedure for adjusting the position of the roller.
After the belt is tensioned as required, the roller is again fixed with a bolt, which is tightened with force with a wrench.
The method has two advantages:
- There is no need to loosen and re-fasten the mountings on the generator.
- You can check the belt tension during the adjustment process.
Please note that after the belt has been tensioned, regardless of the method, additional checks are required.
Start the engine, then turn on the electrical appliances - the more, the better (air conditioning or heater, high beams, tape recorder, heated glass, etc.).
If the light does not go out, there is no whistle from under the hood, then everything is fine.
Attention! It is recommended to adjust the drive belt tension at intervals of 15,000 km or more often. This must be done because the belt stretches over time and the tension force decreases. It needs to be changed every 60,000 km.
Some imported cars do not require adjustments.
The roller is tensioned automatically using springs. However, there are quite a few such models and even on one car model, some copies may not have such an option.
Conclusion
After the belt tension has been adjusted, you should turn the crankshaft two or three times (this is done with a wrench).
After this, you need to check again whether the degree of tension has changed. This step must be done regardless of how the adjustment was carried out.
To make sure the settings are correct, it is advisable to start the engine and drive the car for 1-2 km, then check the tension again.
If you cannot do the work yourself or you are not sure how to tension the belt, then contact specialists at a service station.
If adjustment is not possible because the tensioners are in the extreme position, this means that the belt has stretched and you need to buy a new one.
It is advisable to change it, even if it seems to be working. Replacement frequency is 50-80 thousand km , depending on the make of the car.
When replacement is required
As you already understand, there are several ways to diagnose problems with the alternator belt.
There are several basic checking methods to get an answer about the current state of the node.
- Determination method by ear. So you may hear whistling and constant noise. The first symptom is not fatal, but already indicates the poor condition of the belt. In the second case, everything is much more serious;
- Visual inspection. When examining the condition of the belt, you can find breaks, cracks, traces of abrasions, frayed edges, pulley displacement, threads that have appeared, oil stains on the belt surface, etc.;
- Simple logic and observation. Many motorists know that initially a low-quality belt was used in the generator unit. You shouldn't expect long-term work from him. Also, some cars have a sensor that monitors the condition of the generator.
The belt may wear out due to natural reasons during operation. But problems often arise from the tension mechanism. As a result, the belt itself, as well as the components associated with it, suffer.
A simple replacement is not enough here. More serious repairs will be required with partial or complete replacement of generator parts.
It is not difficult to cope with the independent replacement of such a unit as the alternator belt. Owners of many cars took everything into their own hands.
Recommendations
The operating principle of tensioning devices may differ from those described due to improvements in the parts used. The updated adjustment algorithm is described by the manufacturer of the units in the accompanying instructions.
For the comfort of drivers and passengers, the creators of modern cars equip their models with additional equipment. Often, the timing belt is used to drive not only the generator, but also the power steering hydraulic pump or air conditioning supercharger. An attempt to correctly tension the alternator belt yourself and take into account the characteristics of the driven equipment is fraught with error and unjustified loss of engine power.
