How to eliminate “whistle” of the alternator belt

Inspection of the belt and search for the reasons of its whistling

When using the car, the owner faces many problems, including the sticky situation with the alternator belt. It seems like whistling for no reason and it’s not so easy to guess at once why it happens. In this case, we do not talk about a worn or old belt. Everything is clear in such a situation, it is necessary to replace it and that’s all. Everything is much more interesting, and we will look for a cause and effect relationship as in a thrilling detective story.

So why does a new alternator belt «whistle»? It turns out, there are several reasons for this, and all of them are described below.

Few words about auxiliary belt

Belt drive is the most common way of transmitting rotation to the generator rotor. This method has been used for a long time and differs from others in its simplicity, i.e. there are only two pulleys on the shafts that are connected by the belt.

The belt fulfils a lot of functions. It is responsible for transmitting rotation from one pulley to the other. It is necessary to know that one part of the belt is tightened more than the other. It is the difference of these tensions that determines the pulling capacity and its coefficient.

The belt provides accurate transmission and is noiseless in operation. High-quality products are able to resist continuous loads, smooth impacts and jerks. They are compact and take up minimum space, but they activate several important car components at the same time, i.e. a generator, a pump, an air conditioning compressor and a steering booster pump.

The generator rotor should constantly rotate. Belt joint with the crankshaft facilitates it. Pulleys screwed onto the shafts of the generator and crankshaft are connected with the belt that should be flexible.

The “whistle” of the belt is similar to a terrible clank. It is caused by the fact that the belt slips through. The sound of such a whistle is unpleasant and can be heard far away. Of course, it is not recommended to drive in such a situation.

Whistle of the belt and its reasons

Some drivers suggest that the belt has been of poor quality. They replace it, but everything repeats again. For this reason, it is recommended to inspect the entire belt drive in order not to lose precious time and extra money. A car owner should analyze the conditions under which the whistle appears. It is the most useful way of understanding the reason of whistling.

The inspection includes the following:

• the integrity of the belt is checked (we agree that today even new products can be of poor quality);
• the degree of tension is checked (as you know, the belt often squeaks due to the low tension);
• the cleanliness of the shaft (another reason for the «whistle», as described in detail below);
• the line of two pulleys is checked for displacement.

Five main reasons for the generator whistle

The following is a list of the most common reasons for the alternator belt «whistle»:

1. Car parts should be clean. This is an important rule that a car owner should follow. Oil that gets on the belt or shaft unintentionally causes an unpleasant squeak. This happens due to the fact that the belt loosens its grip to the shaft surface of and slips through.
   The problem can be solved by removing the belt and cleaning the oil.
2. The belt can sag and low tension causes “whistle”. The solution is quite obvious — it is necessary to look under the hood, check how the belt is tightened, and if it is weak, tighten it.
3. “Whistle” can start due to the incorrect line of pulleys. As you know, two pulleys should be strictly along the same line and a slight decline leads to an unpleasant sound.It is necessary to check the displacement and set the pulleys as required.
   It is necessary to check the displacement and set the pulleys as required.
4. Too tight belt can also lead to «whistle». Car owners probably know that a very tough belt does not allow the pulleys to rotate normally. Especially often this situation is observed in the cold season and the whistle stops as soon as the engine warms up and the belt recovers its shape;
5. Damaged bearing can cause “whistle” of the auxiliary belt. Replace the bearing and the problem is solved.

The above mentioned provisions are basic. But it does not mean that there can be no other reasons. The most important thing is to respond to the problem swiftly and take prompt actions to eliminate them, then you’ll forget how the alternator belt whistles.