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?
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: Q: Radiator hose rubbing on pully or a belt

If the accident caused the hose to move closer to the pulley then you may not have much choice but to get the body shop to pull the frame back. If you can move the hose then you could use...

Q: Honestly is the upkeep on an Audi very pricey??

You did not specify the year, make and model of Audi you want to purchase. I can say a few things about the repairs. First there are very few dealers and shops that can work on any problems or maintenance...

Q: The car cranks but occasionally wouldn't start

If the battery is going dead after a couple of days then you have an issue with something drawing the battery down. A battery that is low may not be able to start the engine since the starter will take...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
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...