Audi 4.2L V8 Accessory Serpentine Belt Tensioner 079903133R

Premium Accessory Belt Tensioner for Audi 4.2L V8

Maintain stable accessory-belt tension with this replacement serpentine / V-ribbed belt tensioner, reference 079903133R. The assembly is designed for selected Audi 4.2L V8 applications and replaces earlier 079903133C, 079903133D and 079903133E references.

Material & Construction

The tensioner combines a rigid cast-metal mounting body, precision pulley, steel fasteners and an internal spring-loaded tensioning mechanism. Its job is to keep the accessory belt running with controlled tension as engine speed and accessory loads change.

Function & Benefits

• Maintains correct tension on the accessory drive belt.
• Helps reduce belt flutter, slip and unwanted drive-system noise.
• Supports stable operation of belt-driven accessories.
• Replaces worn pulley bearings, weak tensioning action or a damaged tensioner assembly.

Reference Numbers

Current Reference: 079903133R
Replaces: 079903133C, 079903133D, 079903133E.

Match the reference number, mounting layout and pulley position with the original component before installation.

How to Replace

1. Allow the engine to cool and disconnect the battery according to the vehicle service procedure.
2. Record the accessory-belt routing or photograph it before removal.
3. Relieve belt tension using the correct tensioner tool and remove the belt from the tensioner pulley.
4. Remove the tensioner mounting hardware and take out the old assembly.
5. Install the replacement tensioner and torque the fasteners to the vehicle specification.
6. Route the belt correctly over every pulley, then release the tensioner slowly.
7. Check belt alignment and run the engine briefly to confirm smooth, quiet tracking.

When to Replace

Replace the tensioner when there is pulley-bearing noise, visible belt flutter, weak spring force, belt tracking problems or excessive movement from the tensioner arm.

FAQ

What part number is this?
The current reference is 079903133R.

Which earlier numbers does it replace?
079903133R supersedes 079903133C, 079903133D and 079903133E.

What does the belt tensioner do?
It applies controlled spring force to the accessory belt so the belt remains properly tensioned across the pulley system.

Should the belt be replaced at the same time?
If the existing belt shows cracking, glazing, fraying or contamination, replacing it during tensioner service is recommended.

What should be checked after installation?
Confirm correct belt routing, centered tracking on every pulley and smooth operation without chirping, vibration or belt wander.