VW Beetle, Golf And Jetta: Broken Tensioner, Root Cause Of Failure Is Alternator Pulley

VW Beetle, Golf And Jetta: Broken Tensioner, Root Cause Of Failure Is Alternator Pulley

This type of failure is the result of severe vibrations in the accessory belt drive system. While a broken tensioner may be the result, the root cause often lies elsewhere in the system.

Models: 1998-2004 VW Beetle, Golf, Jetta

It is possible that excessive tensioner movement or a broken tensioner assembly may be observed as illustrated below.

VW Belt TensionerThis type of failure is the result of severe vibrations in the accessory belt drive system. While a broken tensioner may be the result, the root cause often lies elsewhere in the system. These vehicles come from the factory with an overrunning alternator decoupler Pulley. OAD pulleys are engineered to reduce noise, vibration and harshness in the accessory belt drive system while reducing belt tension. A reduction in belt tension will lead to an increased lifecycle of the accessories and improved gas mileage. However, OAD pulleys are wear items and will eventually fail. If left unchecked, a failed OAD pulley will result in excessive and abnormal vibrations in the belt drive system, which may eventually lead to the catastrophic tensioner failure pictured above.

Another often-overlooked cause of the broken tensioner seen above is the result of incorrect servicing of the OAD pulley. If an OAD Pulley has been mistakenly replaced with a one-way clutch pulley or a solid pulley, the belt tensioner is forced to absorb excessive and irregular vibrations that otherwise would not exist.

Ultimately, both of these scenarios will result in the hydraulic strut attempting to compensate for the additional vibrations in the belt drive system. Unfortunately, the tensioner is not designed to withstand these conditions and may eventually break, as pictured above. Gates recommends replacing the ADP whenever the 38192 tensioner is replaced.

Courtesy of Gates.

You May Also Like

Ford Adaptive Cruise Control Alignment Process

Follow these steps for proper horizontal alignment of the cruise control module radar sensor.

• 2010-2017 Taurus, Explorer, Edge, Flex, Fusion, MKS, MKX, MKT, MKZ

• 2015-2017 F150, Mustang, and MKC 

• 2017 Super Duty, Escape, and Continental

This is information on setting up and completion steps for proper horizontal alignment of the cruise control module (C-CM) radar sensor.

Chrysler’s Totally Integrated Power Module Simplifies Circuits

The symptoms of a failing TIPM can vary depending on the vehicle. Check out your options for this repair.

Trakmotive Tech Tip: Window Regulator Installation

Here are eight tips to make your next window regulator replacement easier.

Multi-Spark Ignition Systems

You may have seen the stories about plasma or laser ignition systems that promise to give new life to the internal combustion engine. But while these ignition systems have yet to make it to market the latest ignition innovation still uses a coil and spark plug.

VIDEO: How Modules Manage Alternator Power

Andrew Markel discusses power flow through the electrical system on a vehicle, and how the modules help provide the right amount of power to different components. Sponsored by Valeo.

Other Posts

Power Window Regulator Replacement

Blindly replacing a window regulator and motor assembly may not solve a customer’s problem.

Beyond the Warranty

What does it take to keep a car going for 120,000, 180,000 or 250,000 miles? The key is maintenance and inspection. 

Belt Service For Hybrid and Stop/Start Systems

Knowing how to “force start” a hybrid vehicle can be helpful if you are trying to diagnose a noise problem.

Caring For AGM And Flooded Car Batteries

Faulty battery cables, if loose, corroded, or damaged, can lead to power drainage.