21405887 Boss | Genuine Volvo Penta Part

🔧 Product Description

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.

🚤 Compatibility

• Engine Family: D

Full model list at the end of this description.

⚙️ 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
• Engine type: D13 inline-six turbocharged marine diesel

🔌 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

🛠️ Service Notes

• A boss is the threaded mounting point a sensor or fitting screws into — clean the threads and the sealing face and clear away soot, scale or old sealant before anything is fitted to it
• Where the boss is welded or bolted into a pipe or housing, make sure its sealing face is flat and undamaged and fit a new gasket or sealing washer if the original had one
• Never leave a boss open: fit the correct plug or blanking screw, sealed as the manual specifies, if nothing is mounted in it
• Start the sensor or fitting by hand to avoid cross-threading and tighten to the figure in the workshop manual for your engine; a stripped boss usually means renewing the part it is fitted to
• Check the joint for leaks with the system hot and running afterwards and, where the boss carries a sensor, confirm the sensor reads correctly

🔄 Supersession & Cross Reference

OEM / Related Numbers

• 23011585 - related SCR muffler
• 23154165 - related wet 6-inch exhaust riser

📦 Condition

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

🔎 Full Model Compatibility

Typically suits:

• Volvo Penta D13C3-B MH, D13C1-B MH, D13C4-B MH, D13C2-B MP, D13C2-A MP, D13C4-A MP, D13B-E MG, D13B-E MG (FE), D13B-F MG, D13B-F MG (FE), D13B-N MH, D13B-N MH (FE), D13C4-B MP, D13C5-B MP, D13C6-A MP, D13C1-A MH, D13C2-A MH, D13C1-B MG, D13C3-B MG, D13C2-B MG, D13C4-B MG, D13C5-A MP, D13C2-A MG, D13C1-A MG, D13C7-B MP, D13C8-B MP, D13C9-A MP
• Volvo Penta D16C1-E MG, D16C1-F MG, D16C2-E MG, D16C1-E MH, D16C1-F MH, D16C2-E MH