# 3581770 Volvo Penta Filler Cap | Genuine Used Part

🔧 Product Description

  

Genuine Volvo Penta Heat-Exchanger Coolant Filler Cap - Part Number: 3581770

  

A genuine used Volvo Penta filler cap for the engine heat exchanger and closed freshwater-cooling circuit.

  

This component is a coolant-system filler cap rather than an engine-oil filler cap. It seals the heat-exchanger filling neck and maintains the specified pressure in the freshwater cooling system.

  

⚙️ Key Features

  

• Genuine Volvo Penta heat-exchanger filler cap

• Correct part number 3581770

• Cooling-system component

• Seals and pressurises the freshwater circuit

• Used on MD and D2-series marine diesels

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 3581770 established Volvo Penta filler-cap reference

• Listed as discontinued by some suppliers

• No confirmed direct supersession

  

OEM / Related Numbers:

  

• 3581770

• VOP3581770

• 3581924 related heat-exchanger housing

• 861898 related air inlet

• 861904 related cooling-system tube

• 861906 related exhaust-pipe elbow

• Pressure rating must match the original Volvo Penta cap specification

  

Aftermarket / Verified Equivalents:

  

• No verified direct aftermarket cap with confirmed Volvo pressure calibration

• Genuine used or new-old-stock 3581770 caps are the safest replacement

• Generic radiator caps must not be fitted unless pressure, neck depth and sealing dimensions are verified

  

🚤 Compatibility

  

Commonly used on:

  

• Volvo Penta D2-55

• Volvo Penta D2-55B

• Volvo Penta MD2010C / MD2010D

• Volvo Penta MD2020C / MD2020D

• Volvo Penta MD2030C / MD2030D

• Volvo Penta MD2040A / MD2040B / MD2040C / MD2040D

• Selected 20x0C and 20x0D heat-exchanger assemblies

  

• Engine Type: Volvo Penta compact marine diesel with closed freshwater cooling

• Year Range: Primarily late-1990s through 2000s

• Fitment Requirement: Confirm filler-neck depth and pressure rating

  

🔌 Function

  

The cap seals the heat exchanger, allows coolant filling and maintains cooling-system pressure to raise the coolant boiling point.

  

Common signs of failure:

  

• Coolant leaking around the filler neck

• Cooling system will not hold pressure

• Coolant expelled into the overflow

• Damaged cap seal or spring

• Overheating caused by pressure loss

  

📦 Condition

  

• Genuine used part

• Removed from running engine where applicable

• In good working condition unless otherwise stated

## Details

- **Price:** 20.0 AUD
- **Vendor:** Sawley's Auto and Marine
- **Tags:** Sawley’s AAM Used Parts – Oil Pumps & Components | Engine Lubrication Systems

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 20.00 AUD | In stock |

## Images

- 3581770 Volvo Penta Filler Cap | Genuine Used Part
- 3581770 Volvo Penta Filler Cap | Genuine Used Part
- 3581770 Volvo Penta Filler Cap | Genuine Used Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/3581770-volvo-penta-filler-cap-genuine-used-part)
> Updated: 2026-07-20