Tech Tip: When to Change the Automatic Drive Belt Tensioner – UnderhoodService

Tech Tip: When to Change the Automatic Drive Belt Tensioner

While CARDONE water pumps, alternators, smog pumps and power steering pumps all do different jobs, they all have one thing in common: they are belt-driven. Without a properly functioning belt-drive system, these units can't work as designed. Most late-model vehicles use an automatic belt-tensioning device of some design.

Application:
All vehicles with serpentine belt-driven accessories (water pumps, alternators, smog pumps and power steering pumps).

Problem:
Premature failure or improper operation of belt-driven units.

Cause:
Possible failure of the belt-tensioning device.

Solution:
While CARDONE water pumps, alternators, smog pumps and power steering pumps all do different jobs, they all have one thing in common: they are belt-driven. Without a properly functioning belt-drive system, these units can’t work as designed. Most late-model vehicles use an automatic belt-tensioning device of some design. An over-tensioned belt causes premature failure of the unit, belt or both. An under-tensioned belt prevents these units from working reliably, sometimes causing them to not work at all. Both scenarios can lead to unnecessary replacement of the wrong component, increased warranties and cause customer dissatisfaction.

Installation Tip:
Follow the instructions below to see if your tensioner needs replacing.

1. Engine running, drive belt on (Remember, safety glasses and caution are required):
A. Listen for rattles and squeaks.

B. Inspect the drive belt alignment as it tracks from pulley to pulley:
• If the belt is tracking dead center on the pulleys, the tensioner is good.
• If the drive belt is tracking from one side to the other (belt wandering) or belt edge-wear is observed, replace the tensioner.

2. Engine off, drive belt off:
A. Look for signs of rust, especially between the tension arm and base. Replace tensioner.

B. Move the arm on the tensioner:If it feels rough and tight, replace the tensioner.If it’s smooth and easy to move, don’t replace the tensioner.

C. Manually spin idler pulley by hand:
• If it’s smooth with no wobble, no tensioner replacement needed.
• If the pulley turns rough, grinds or wobbles, replace the tensioner.

Please refer to your vehicle’s service manual for specific instruction concerning proper operation of the belt system, its servicing, replacement and adjustment.

Note: This Pro Tech bulletin is supplied as technical information only and is not an authorization for repair.

Tech Tip courtesy of CARDONE.

For additional information on products offered by CARDONE, visit www.cardone.com.

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