Parts Catalog Accessories Catalog Tech Info Tech Forums
 
  Search our site:    
View Recent Cars  |   Cart  | Project List | Order Status | Help    
 >  >
Serpentine Belt Tensioner and Pulley Replacement
 
Bookmark and Share

Pelican Technical Article:

Serpentine Belt Tensioner and Pulley Replacement

Jared Fenton

Time:

2 hours2 hrs

Tab:

$130

Talent:

***

Tools:

T50 Torx driver, screwdrivers

Applicable Models:

Porsche 955 Cayenne (2004-10)
Porsche 955 Cayenne GTS (2008-10)
Porsche 955 Cayenne S (2003-10)
Porsche 955 Cayenne Turbo (2003-10)
Porsche 955 Cayenne Turbo S (2006-10)

Parts Required:

New belt tensioner shock, pulleys

Hot Tip:

Check all pulleys for resistance

Complementary Modification:

Replace serpentine belt

The Porsche Cayenne uses a serpentine belt to drive the various ancillary components on the engine. This includes the alternator, A/C compressor, power steering pump and the water pump. The serpentine belt is kept in place by a small pneumatic strut mounted to a bracket with an idler pulley. This is called a belt tensioner. Over time, the serpentine belt can stretch. The tensioner setup is designed to allow a certain amount of flex to account for stretching as well as vibration.

Over time, the pneumatic strut that holds tension on the belt can wear out, causing less tension to be applied to the serpentine belt. Additionally, the bearings in the idler pulleys can also begin to fail causing noise. If you ignore a bad bearing long enough, the pulley can lock up and snap the belt.

To inspect and/or replace the tensioner or pulleys, first remove the serpentine belt from the engine. Please see our article on Serpentine Belt Replacement for more information.

Once the serpentine belt is removed, you'll want to spin all three pulleys and check that they all move freely with no noise or side-to-side play. If the pulley is binding, makes noise, or the contact surface is damaged, you'll want to replace it.

You'll also want to check the tension on the pneumatic strut. Typically, it should take a good amount of force to relieve tension on the belt. If it is easy to compress the strut and you hear a good amount of belt squeal, think about replacing the strut.

Shown here is the belt routing diagram at the front of the engine compartment.
Figure 1

Shown here is the belt routing diagram at the front of the engine compartment. This diagram shows the location of the idler pulleys (green arrows), the tensioner pulley (blue arrow) and the belt tensioner strut (yellow arrow). The idler pulleys have a grooved surface the belt rides in while the tensioner pulley is smooth.

I've found that the best way to remove the tensioner assembly is to first remove the tensioner strut.
Figure 2

I've found that the best way to remove the tensioner assembly is to first remove the tensioner strut. It is held in place with two T50 Torx bolts. First remove the upper mounting bolt (green arrow). Also pry the plastic cover off the end of the tensioner arm as shown here (yellow arrow). If you look at the surface of the tensioner pulley, you can see the grooves worn into the surface from the belt (blue arrow). We will be replacing this pulley.

Shown here is the lower T50 Torx bolt that holds the tensioner strut to the engine (green arrow).
Figure 3

Shown here is the lower T50 Torx bolt that holds the tensioner strut to the engine (green arrow). Remove the bolt and remove the strut from the engine compartment.

Loosen and remove the T50 Torx bolt holding the tensioner assembly to the engine (green arrow).
Figure 4

Loosen and remove the T50 Torx bolt holding the tensioner assembly to the engine (green arrow). Now carefully remove the tensioner assembly from the engine compartment.

Shown here is the idler pulley on the right side of the engine (green arrow).
Figure 5

Shown here is the idler pulley on the right side of the engine (green arrow). If the pulley needs to be replaced, pry the plastic cover off and remove the T50 Torx bolt holding the pulley to the engine.

Shown here is the idler pulley on the left side of the engine (green arrow), just next to the crankshaft pulley.
Figure 6

Shown here is the idler pulley on the left side of the engine (green arrow), just next to the crankshaft pulley. As before, check the pulley for wear. Pry the plastic cover off the pulley and remove the T50 Torx bolt holding it on.

In this picture we have the tensioner assembly removed from the engine to remove the tensioner pulley.
Figure 7

In this picture we have the tensioner assembly removed from the engine to remove the tensioner pulley. Begin by removing the plastic cover off the front of the pulley (green arrow).

Now remove the T50 Torx bolt holding the pulley on.
Figure 8

Now remove the T50 Torx bolt holding the pulley on. You may need to place the assembly in a vise to remove the bolt.

Shown here is the new tensioner pulley (on the left) next to the old pulley (on the right).
Figure 9

Shown here is the new tensioner pulley (on the left) next to the old pulley (on the right). Over time, the belt will wear grooves into the pulley and eventually will wear the belt out faster.

Shown here is a new strut showing its orientation.
Figure 10

Shown here is a new strut showing its orientation. You'll notice the "top" marking cast into the strut body. Make sure to install the new strut with the arrows pointed up as shown here.

Bookmark and Share
Comments and Suggestions:
Subbu Comments: Is there a trick to pry the plastic cover on the passenger side idler pulley? Any special tool? It is so tight in there that I am unable to pry it off. Thanks!
June 3, 2016
  Followup from the Pelican Staff: No special tool. Just a small flathead screwdriver. - Nick at Pelican Parts  
Frank Comments: How many miles is a serpitine belt good for? How many miles
are tensioners good for?
December 30, 2015
  Followup from the Pelican Staff: belts usually last anywhere from 40 - 60k. Tensioners about 60 - 100k. - Nick at Pelican Parts  

  Search our site:    

View Cart & CheckOut | Project List | Order Status |  Help    

 

[Home] [Customer Service] [Shopping Cart] [Project/Wish List]
  [Privacy Statement]  [Contact Us] [About Us] [Shipping] [Careers]

Copyright © Pelican Parts Inc. -    DMCA Registered Agent Contact Page

Page last updated: Mon 12/5/2016 02:32:10 AM