Engine - Drive Belt Wear/Tensioner Seizure

NO: 21-27
DATE: 4-18-2008
MODEL: C30 / 540 / V50 / C70
YEAR: 2004 -
ENGINE CODE: 38, 39, 67, 68
SUBJECT:
Correct Auxiliary Belt Tensioner Alignment

NOTE!
If this is a printed version of a TNN, first check for the latest online version.

Description:
It has been found that a misalignment of the auxiliary belt tensioner can cause noise, damaged belt or tensioner seizure.

Cause:
Contact between inner and outer belt tensioner.

Service:
Follow inspection and adjustment procedure below.

Note!
Some variation in the illustrations may occur, but the essential information is always correct.

For removal/installation of the auxiliary belt, see:
Removal, replacement and installation
Engine with mountings and equipment
Engine
Transmission

Checking belt tensioners

The outer/lower belt tensioner has a substantial amount of play between; screws, screw holes, locating pins and holes for locating pins.
This can cause contact between outer and inner belt tensioners.
The distance must be 2.5 mm (0.09 in), but can vary between 0 and approximately 3 mm (0.0-0.11in)





The image shows correctly installed belt tensioner.

The distance between the inner belt tensioner and the deflection limiter on the outer belt tensioner should be 2.5-3.0 mm(0.09-0.11 in). Check the distance using a feeler gauge.





The image shows incorrectly installed belt tensioner.

The deflection limiter on the outer belt tensioner is against the inner belt tensioner.
Remove the outer auxiliary belt.

Adjust the belt tensioner's position by removing the screw for the outer belt tensioner and installing it according to the next step.





Installation of belt tensioner

When installing the outer belt tensioner, turn the belt tensioner clockwise (1) and hold it in position.

Tighten the screw (2).

Tightening torque: 42 Nm. (30 ft-lb)

This will allow clearance between the upper and lower tensioner.

Caution!
Check that the position of the belt tensioner is correct; adjustment must only be carried out when the belt has been removed.

Install the belt.





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