# 21281430 Expansion Plug | Genuine Volvo Penta Part

## 🔧 Product Description

Genuine Volvo Penta expansion plug used to close a machined core or service opening in the cylinder block or flywheel-housing area. Correct diameter, interference and installation depth are essential to prevent coolant or oil leakage.

## 🚤 Compatibility

Typically suits:

-   Volvo Penta D1-30
-   Volvo Penta D1-30B
-   Volvo Penta D1-30F
-   Volvo Penta MD2010B
-   Volvo Penta MD2010-C
-   Volvo Penta MD2010-D
-   Volvo Penta MD2020B
-   Volvo Penta MD2020-C
-   Volvo Penta MD2020-D
-   Volvo Penta MD2030
-   Volvo Penta MD2030B
-   Volvo Penta MD2030-C
-   Volvo Penta MD2030-D

-   **Engine Family:** D, MD
-   **HP Range:** 30 HP

## ⚙️ Key Features

-   Genuine Volvo Penta engine-block expansion plug
-   Precision diameter for the assigned machined bore
-   Closes a casting core or service opening
-   Requires correct seating depth and clean bore
-   Replace if corroded, leaking or disturbed
-   Engine type: Volvo Penta marine or industrial diesel
-   2 used per assembly

## 🔌 Function

Permanently closes the assigned casting opening and retains coolant or oil within the engine passage.

## ⚠️ Common Signs of Failure

-   Coolant or oil seeping from a machined opening in the block or flywheel housing area
-   Rust staining or a crusty deposit trailing down the casting below the plug
-   Plug visibly dished, proud of the casting, or pushed part way out
-   Corrosion pinholing through the face of the plug
-   On removal, the machined bore found corroded or scored so the new plug cannot grip

## 🛠️ Service Notes

-   Clean the bore back to bright metal and check it for scoring before pressing the new plug in - a corroded bore is the usual reason a replacement leaks
-   Drive the plug to the specified depth; too deep or too shallow both leak
-   Supersedes 3886429 and 861803, the earlier number catalogued as a plug blank

## 🔄 Supersession & Cross Reference

### OEM Supersession Chain

-   21281430 → Supersedes 3886429

### OEM / Related Numbers

-   861803 earlier number superseded by this part
-   3886429 earlier number superseded by this part
-   3582307 - associated cylinder-block reference
-   3886427 - other position-specific block-plug references; not interchangeable without schematic confirmation
-   3583696 - other position-specific block-plug references; not interchangeable without schematic confirmation
-   3583697 - other position-specific block-plug references; not interchangeable without schematic confirmation
-   861805 - other position-specific block-plug references; not interchangeable without schematic confirmation
-   3807215 - other position-specific block-plug references; not interchangeable without schematic confirmation
-   861806 - other position-specific block-plug references; not interchangeable without schematic confirmation

## 📦 Condition

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

## Details

- **Price:** 26.11 AUD
- **Vendor:** Volvo Penta
- **Type:** Fasteners & Fixings
- **Tags:** Volvo Penta

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 26.11 AUD | In stock |

## Images

- 21281430 Expansion Plug | Genuine Volvo Penta Part
- 21281430 Expansion Plug | Genuine Volvo Penta Part - photo 2 of 2

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/21281430-expansion-plug-genuine-volvo-penta)
> Updated: 2026-10-11