Q: How Do Belt Tensioners Work?

asked by on

How do belt tensioners work?

The belt tensioners in your car work to ensure that there is enough tension on your serpentine belt, or other drive belts, so that everything in your engine compartment (your alternator, water pump, air conditioning compressor, etc.) operates the way it should. If the belt is too loose, it won’t drive the pulleys properly.

Belt tensioners come in two varieties; automatic and manual.

The automatic belt tensioner is a spring-loaded idler pulley that maintains constant tension on the drive belt at all engine speeds. The faster that the engine turns, the belt gets stretched more which actually makes the belt loose. The automatic tensioner keeps the belt from becoming loose when the engine speed increases.

Manual belt tensioners are idler pulleys that are tensioned by either tightening a threaded rod or a bolt. These tensioners do not maintain constant belt tension when the belt stretches, so they must be checked periodically and adjusted as needed.

If you think you’re having a problem with the belt tensioner, you will want to have the car checked as soon as possible to prevent any further damage. A technician from YourMechanic can help you service or replace your belt tensioner for you if necessary.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. How Do Belt Tensioners Work?

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Gas pedal pressed to floor before car accelerates

Hello, we will be happy to assist you. I would suggest that you have a technician use a capable scan tool to perform a function test on the vehicle. Doing so will test most of the sensors on the vehicle...

Q: What should I know about the brake system?

While your car’s brake system is pretty low maintenance (not NO maintenance, though), there are several things that you need to know to ensure that it stays in good condition and you stay safe on the road. Here’s the most...

Q: Timing belt ripped and after weird loud sound

Good question. I don't think there was any damage done to your car. Belts break all the time, just put a new one on and it'll be fine. Your steering wheel became hard to turn because your power steering pump...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...