Belt Tensioner

The Cummins Belt Tensioner (OEM 3937553) is a replacement automatic tensioner designed for compatible Cummins diesel engines. Fitted within the engine's auxiliary belt drive, the tensioner maintains the correct belt tension as the engine operates, helping prevent belt slip while allowing the belt to run smoothly around the associated pulleys.

Designed for the demanding conditions of heavy-duty diesel engines, the tensioner is subjected to continuous vibration, rotation and changes in belt load. Replacing a worn or damaged tensioner helps maintain correct belt tracking and tension, reducing the risk of premature belt wear and failure of belt-driven engine accessories.

FUNCTION AND OPERATION

• Maintains the correct tension in the engine auxiliary drive belt
• Helps prevent belt slip during engine operation
• Compensates for changes in belt tension during operation
• Helps maintain correct belt tracking across the drive pulleys
• Reduces excessive belt vibration and movement
• Replacement for a worn, seized or damaged original tensioner

TECHNICAL DETAILS

• OEM Number: 3937553
• Manufacturer: Cummins
• Component: Belt tensioner
• Type: Automatic belt tensioner
• Pulley diameter: Approximately 74 mm
• Pulley width: Approximately 39.5 mm
• Application: Selected Cummins diesel engines

TYPICAL APPLICATIONS

• Cummins B Series engines
• Cummins 6BT engines
• Cummins ISB engines
• Cummins QSB engines
• Fan and alternator belt drives
• Construction, agricultural and industrial equipment

IMPORTANT INFORMATION

A worn belt tensioner can cause belt squealing, vibration, poor belt tracking and accelerated belt wear. The tensioner should be inspected whenever the belt is replaced, checking for excessive movement, bearing noise, pulley wear and loss of tension.

Always confirm the engine model and serial number before ordering to ensure the correct tensioner is fitted. The associated belt, pulleys and other belt-driven components should also be inspected during replacement.

DELIVERY OPTIONS (UK mainland only)

Next Day Delivery*
£11.95 or FREE for orders over £150
Orders placed before 4pm Monday to Friday will be delivered on the next business day.
Orders placed after 4pm on Friday will be delivered the following Tuesday.
*Next day delivery applies to stocked items only. Availability can be found on the product pages.

Premium Delivery*
£30.00 for delivery before 10:30am
£25.00 for delivery before 12:30pm
*Premium delivery applies to stocked items only. Availability can be found on the product pages.

For all other countries, please click here for full delivery information.

**Separate carriage charges apply to bulk products such as 205L barrels.