# 21405887 Boss | Genuine Volvo Penta Part

🔧 Product Description

  

Genuine Volvo Penta D13 Exhaust NOx Sensor Boss - Part Number: 21405887

  

A precision threaded boss used in selected Volvo Penta D13 wet-exhaust, exhaust-flange and SCR muffler assemblies. It provides the correct mounting and gas-exposure position for the applicable NOx or exhaust-aftertreatment sensor.

  

⚙️ Key Features

  

• Genuine Volvo Penta exhaust-system boss

• Correct sensor thread and seating geometry

• Designed for high-temperature exhaust service

• Used in wet-exhaust and SCR-related D13 arrangements

• Provides accurate sensor positioning in the exhaust stream

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 21405887 (current catalogued reference)

  

OEM / Related Numbers:

  

• 23011585 - related SCR muffler

• 23154165 - related wet 6-inch exhaust riser

• Associated NOx sensor and sealing hardware

  

Aftermarket / Verified Equivalents:

  

• No aftermarket equivalent

  

🚤 Compatibility

  

Commonly used on:

  

• Volvo Penta D13 marine exhaust and aftertreatment systems

  

Typically suits:

  

• Engine models:

• D13B-N MH

• D13B-N MH (FE)

• D13C1-A MG SCR-equipped applications

  

• HP Range: Engine-rating dependent

• Engine Type: D13 inline-six turbocharged marine diesel

• Year Range: Exhaust-system and emissions-package dependent

  

🔌 Function

  

Provides the threaded mounting point that positions the exhaust or NOx sensor in the gas stream.

  

Common signs of failure:

  

• Damaged or stripped sensor thread

• Exhaust leakage around the boss

• Corrosion or cracking at the welded joint

• Sensor cannot be tightened or removed correctly

• Incorrect sensor reading caused by a damaged mounting seat

  

📦 Condition

  

• Genuine Volvo Penta part

• Brand new

• Supplied in original or equivalent packaging

## Details

- **Price:** 68.38 AUD
- **Vendor:** Volvo Penta
- **Tags:** Volvo Penta

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 68.38 AUD | In stock |

## Images

- 21405887 Boss | Genuine Volvo Penta Part

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> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/21405887-boss-genuine-volvo-penta)
> Updated: 2026-08-02