How To Change Serpentine Belt 6.7 Cummins 

The Cummins 6.7L diesel engine's serpentine belt system drives a variety of components. It includes the water pump, steering, heating, and air conditioning systems, among other things. Serpentine belts are large, circular bands that, when attached to pulleys, take on the appearance of snakes. 

The Serpentine Belt 


The serpentine belt in a 6.7L Cummins is responsible for providing power to different components. The serpentine belt is wrapped around various pulleys; these are as follows: 


  • Generator 

  • Idler Pulley 

  • P/S Pulley 

  • Accessory Belt Drive 

  • Radiator Fan Pulley 

  • A/C Compression Pulley 

  • Crankshaft Pulley 

  • Accessory Drive Belt Tensioner 

A serpentine belt is also referred to as an accessory belt in some circles. It is a critical engine component—the core engine belt, visible when your vehicle’s hood is opened—that must be maintained. 
Because of the distinctive ridges on this belt, it can be easily noticed or identified. 
Ridges serve to maintain grip when an accessory pulley turns or rotates. 
A serpentine belt is a driving force behind the engine's various accessories. The battery is not the only power source for the engine's accessories, as many people may have once believed.  
In operation, the serpentine belt ensures that spinning motion is originating.  It is either one or both that is transferred from the crankshaft to the accessory pulleys.  
Simply put, this is how engine accessories obtain the power they require to function properly. 
 A serpentine belt also helps supply power to a supercharger if your vehicle is fitted with one.  


Serpentine belt warning signs 


Serpentine belt performance may improve over time as new materials become available. It allows a longer-lasting product to be produced.  But they are still soft material belts that spin rapidly while driving or when the engine is idle.  As a result, it is normal to experience belt problems because of wear. 


Squealing or chirping noises 


When a serpentine belt begins to slip, it produces squealing and chirping sounds. Here are a few sources of slippage: 

  • Belt tension is too low. 

  • Belt stretch 

  • Foreign substance on the belt 

  • Pulleys and belts don't work together counter-clockwise 

To determine which of the possible causes is the root of the problem, take your vehicle in for an inspection.  

Rust and cracks are visible. 


When you inspect your belt on a regular basis, you should look for cracks, missing parts, damaged or separated ribs, or uneven wear. If you notice any of these things, the belt should be replaced. 


Power steering or air conditioning that isn't working properly 


When your power steering or air conditioner starts to fail, make sure to check your belt first before checking the other components. In some cases, worn-out belts can result in a wide range of symptoms. 


A Complete Breakdown 


A broken serpentine belt disables many engine components, making it impossible to drive safely. As a result, you'll need roadside assistance or, if you have one, a spare belt to get you back on the road. 


The Check Engine light will illuminate when there is a problem with the serpentine belt. When using a tuner/programmer, you will receive a DTC warning if the belt is not functioning properly. 


How To Change Serpentine Belt 6.7 Cummins 


You may find replacing this belt difficult the first time. 


  1. Open the hood of your vehicle. 

  1. Remove the tensioner from the A/C pulley and set it aside. 

  1. Taking the airbox out of the equation 

  1. Remove the tensioner from the path by turning it counter-clockwise (undo one bolt). 

  1. Remove your old belt from your closet. 

  1. Install the new belt on each pulley in the manner shown in the diagram, making sure not to forget the tensioner. 

  1. Make sure to follow the serpentine belt diagram, and you will be able to complete the task successfully the first time. 

  1. Once the belt has passed over the tensioner, rotate the tensioner counterclockwise and reinstall the bolt.  

  1. The process of installing the belt comes to an end at this point. Check the tension by reopening the hood, closing the air box, and starting the vehicle. 


What Is the Life Expectancy of a Serpentine Belt? 


The lifespan of a serpentine belt is between 50,000 to 100,000 miles with current technology. Check the belt every 10,000 miles after it has been in use for 50,000 miles to make sure it is not overworked and to ensure it is in good condition. You can also check the tensioner at the same time. 


For all your diesel trucking needs, be sure to visit Pure Diesel Power, where you can browse through their massive selection of diesel engine products. Contact us at 715-254-1833, email us at [email protected], or visit our website,