# 3886225 Expansion Tank | Genuine Volvo Penta Part

## 🔧 Product Description

Genuine Volvo Penta expansion tank from the Cooling System group, weighing 13.11 kg and listed for 14 applications across the D series. It supersedes part number 865123.

## 🚤 Compatibility

Typically suits:

-   Volvo Penta D12C-A MP
-   Volvo Penta D12D-A MG
-   Volvo Penta D12D-A MH
-   Volvo Penta D12D-A MP
-   Volvo Penta D12D-B MH
-   Volvo Penta D12D-B MP
-   Volvo Penta D12D-C MH
-   Volvo Penta D12D-C MP
-   Volvo Penta D12D-D MP
-   Volvo Penta D12D-E MG
-   Volvo Penta D12D-E MP
-   Volvo Penta D12D-F MP
-   Volvo Penta D12D-G MP
-   Volvo Penta D12D-H MP

-   **Engine Family:** D

## ⚙️ Key Features

-   13.11 kg
-   Supersedes 865123
-   14 applications across the D series

## 🔌 Function

Holds the coolant reserve and takes up the expansion as the engine warms, letting air separate out of the circuit and setting system pressure through its cap.

## ⚠️ Common Signs of Failure

-   Coolant loss with no obvious external leak, or steam from the tank
-   Level swinging widely between cold and hot
-   Coolant weeping at a tank seam or the filler neck
-   Engine running hot with air still in the system after bleeding
-   Corrosion or scale visible inside the tank

## 🛠️ Service Notes

-   Renew the filler cap and the tank seals with the tank, as a cap that will not hold pressure causes the same symptoms as a failed tank
-   Refill and bleed the system properly and check the vent pipework, such as air vent pipe 3886012 where fitted, is clear and rising

## 🔄 Supersession & Cross Reference

### OEM Supersession Chain

-   3886225 → Supersedes 865123

### OEM / Related Numbers

-   865123 earlier number superseded by this part

## 📦 Condition

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

## Details

- **Price:** 6520.2 AUD
- **Vendor:** Volvo Penta
- **Type:** Cooling System
- **Tags:** Volvo Penta

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 6520.20 AUD | In stock |

## Images

- 3886225 Expansion Tank | Genuine Volvo Penta Part
- 3886225 Expansion Tank | Genuine Volvo Penta Part - photo 2 of 2

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/3886225-expansion-tank-genuine-volvo-penta)
> Updated: 2026-10-11