How Tight Should a Serpentine Belt Be?

Serpentine Belt is a robust rubber belt that is a crucial part of almost every engine system.

The operation of some of the major parts of the engine system like an air pump, water pump, air conditioning compressor, power steering pump depend on the serpentine belt.

It connects and drives all these peripheral devices of the auto engine system. Needless to say, the serpentine belt plays a key role in the operation of your vehicle.

In caseit does not function correctly, you run the chance of getting stranded any point of time if your steering loses control, or engine is overheated and stops generating power and several other reasons.

Performance & Efficiency of Serpentine Belt

The efficiency of a serpentine belt basically lies in its tension. To mention in common language – tighter the belt is, better will be the output of the devices connected to it.

Be it power steering, air conditioner or anything. The tension in the serpentine belt keeps it tight and straight on the connecting pulleys and prevents it from flipping over.

In case the belt flips, twists and stretches while spinning, it will wear out in less than due course of time and will choke on driving the devices connected to it automatically affecting their performance.

If somehow the tension in the belt is not proper, its operation is going to consume more power. That will definitely halter the overall performance, efficiency, and experience of the vehicle.

Therefore, the tension of the belt should be checked frequently – may be in a fortnight or monthly, along with its general condition.

That said, the serpentine belt should not be too tight also in the engine system. Otherwise, the strain it will put on the pulleys and connecting bearings will be more, eventually consuming more power than required in the running.

The over tightness may also cause premature failure of the bearings and other connected devices.

A Measure of Tightness or Tension

If the tension in the serpentine belt is not right, it will start producing squeaky noise. That is when you have to take the hint and check the position of the belt.


If the corrective measures are not taken in time, the belt will slip over the pulleys and dislodge eventually resulting in the immediate break down of vehicle.

The required measure of tension in the serpentine belt is that it should not deflect more than ½ inch when twisted either way from the middle. If twisted more, the belt is loose, and if twisted less, the belt is too tight.

Either of the positions does not work for the vehicle. The serpentine belt has to be running on the right amount of tension for a good outcome.

How to Tighten a Serpentine Belt?

The above paragraphs explain the need for tightness or tension in the serpentine belt which should neither be loose nor too tight for the efficient running of the system.

So let us have a brief idea about how we can tighten it.

Conventional Process

In traditional car designs, the tension of the serpentine belt is usually governed by a generator placed near the engine.

To adjust the tension in the belt, the generator needs to be moved towards or away from the engine, and the belt is adjusted by tightening or losing the pivot screws on the generator.

For tightening the belt, move the generator away from the engine by a hammer handle or similar tool.

Loosen the screws on the pivot section and pull the belt in. Check the tension and if it is right, bolt the screws back to pivot.

To loosen the belt, move the generator towards the engine by the hammer handle. Loosen the screws on the pivot section and pull the belt out.

Move the generator back in position and check the tension. If the tightness feels right, bolt the screws back to pivot.

Contemporary Process

Modern vehicles generally come with automatic belt tensioners with pulley arrangement. The system has become quite standard for the automobiles now.

Adjusting the serpentine belt tension becomes easier with this system in place. It is also more accessible to operate than moving the generator thing.

To adjust the tension of the belt in the pulley system, reach out to the tensioner pulley. Take the help of manufacturer manual to guide you through the parts of the engine system.

How to Tighten a Serpentine Belt

Pull the one half of the pulley out.

With the help of spanner or similar tool, rotate the screws clockwise and anti-clockwise on the pulley to adjust the tension on the belt.

Check the tension by twisting the belt and measure the twist margin. If the tightness of the belt is right, tighten the screw in place to assert the firmness.

Put the cover of the pulley back in place. Turn on the engine and observe the vibrations of bearings and pulleys, plus the spinning of the serpentine belt.

If the continuation in the movement of the belt is not proper, open the pulley cover and correct bolting of screws on the pulley. Make sure that the alignment of the belt remains intact while adjusting the tension.

Put the pulley cover back and turn on the engine. Until the spinning of the belt becomes smooth, readjust and tighten the screws on the tensioner pulley.

Noticeable Significance

The tension in the serpentine belt is the main factor responsible for its operation. In case you miss to get the right tension on the belt, it is sure to produce noise while in function.

If ignored, the looseness will cause the belt to dislodge, and extra tension will lead to exertion and excess wear of belt.

In both, the situations and performance of the belt and the devices driven by it, is sure to hinder and will lead to cause the vehicle to lose its efficiency eventually.

Given all the above details, it would be wise to pay attention to the general condition of the serpentine belt within the time period stipulated in the manufacturer’s manual.

The tension factor to be looked after frequently, there will be its tightness only, which can get disturbed with the daily strain exerted over the belt and need the corrections.

Rest assured, the life and quality of the belt sustain for a longer period of time. Keep the maintenance of the serpentine belt in your vehicle in check and enjoy your time on the road to the fullest.

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