# 21180308 Tensioner | Genuine Volvo Penta Part

## 🔧 Product Description

Brand-new genuine Volvo Penta mechanical tensioner from secondary-alternator mounting kit 21384685. It adjusts and locks belt 21179870 at the correct tension between pulley 21178941 and the optional alternator.

## 🚤 Compatibility

Typically suits:

-   Volvo Penta D2-55B
-   Volvo Penta D2-55C
-   Volvo Penta D2-55D
-   Volvo Penta D2-55E
-   Volvo Penta D2-55F
-   Volvo Penta D2-50F
-   Volvo Penta D2-75B
-   Volvo Penta D2-75C
-   Volvo Penta D2-75F
-   Volvo Penta D2-60F

-   **Engine Family:** D
-   **HP Range:** 50-75 HP

## ⚙️ Key Features

-   Mechanical adjuster for the secondary-alternator belt
-   Part of kit 21384685
-   Works with bracket 21178401 and pulley 21178941
-   Maintains correct belt tension under charging load
-   Tensioner only; belt and mounting hardware are separate
-   Engine type: Volvo Penta D2 four-cylinder marine diesel

## 🔌 Function

Sets and retains the secondary alternator belt tension so charging output is transmitted without slip.

## ⚠️ Common Signs of Failure

-   Belt squeal under load
-   Adjustment threads seized or stripped
-   Belt repeatedly loosening
-   Bracket or tensioner bending
-   Low charging output from belt slip

## 🛠️ Service Notes

-   Renew the tensioner and the belt together, and while the belt is off check the other pulleys for wear, roughness in the bearing and any wobble
-   Note the belt routing and the tensioner's mounting position and stops before removing the old unit, and check the new one carries the same pulley and offset
-   Locate the tensioner properly on its dowel or stop and tighten it to the workshop manual figures — a tensioner not sitting square will run the belt off line and destroy it
-   Wind the tensioner back with the correct tool or square drive, fit the belt over the pulleys by hand and release the tensioner onto it; never lever a belt on with a screwdriver and never use the tensioner arm as a pry bar
-   Check every rib or tooth is seated in its groove, turn the engine over by hand, then run it up and recheck belt run and tension after the first period of running, following the procedure for your engine

## 🔄 Supersession & Cross Reference

### OEM / Related Numbers

-   Mounting kit 21384685
-   Bracket 21178401
-   Pulley 21178941
-   Belt 21179870

### Other-Brand OEM Numbers

-   VOE21180308

## 📦 Condition

-   Genuine Volvo Penta part
-   Brand new
-   Supplied in original or equivalent packaging

## Details

- **Price:** 346.84 AUD
- **Vendor:** Volvo Penta
- **Tags:** Volvo Penta

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 346.84 AUD | In stock |

## Images

- 21180308 Tensioner | Genuine Volvo Penta Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/21180308-tensioner-genuine-volvo-penta)
> Updated: 2026-08-22