21505623 Air Vent Pipe | Genuine Volvo Penta Part

🔧 Product Description

A formed air-vent pipe used in the expansion-tank circuit on selected Volvo Penta D13B-E cooling systems. It allows trapped air and vapour to return to the expansion tank.

🚤 Compatibility

Typically suits:

• Volvo Penta D13C3-B MH
• Volvo Penta D13C1-B MH
• Volvo Penta D13B-A MP
• Volvo Penta D13B-H MP
• Volvo Penta D13B-G MP
• Volvo Penta D13B-L MP
• Volvo Penta D13B-E MG
• Volvo Penta D13B-E MG (FE)
• Volvo Penta D13B-E MH
• Volvo Penta D13B-E MH (FE)
• Volvo Penta D13B-K MP
• Volvo Penta D13B-N MH
• Volvo Penta D13B-N MH (FE)
• Volvo Penta D13B-B MP
• Volvo Penta D13B-D MP
• Volvo Penta D13B-J MP
• Volvo Penta D13B-M MP
• Volvo Penta D13B-C MP
• Volvo Penta D13C1-A MH
• Volvo Penta D13C1-A MG

• Engine Family: D

⚙️ Key Features

• Genuine Volvo Penta air-vent pipe
• Designed for the D13 expansion-tank arrangement
• Correct factory routing and connection positions
• Works with coolant pipe 21504807
• Supports effective cooling-system deaeration
• Engine type: D13 inline-six turbocharged marine diesel

🔌 Function

Routes trapped air and coolant vapour from the engine cooling circuit to the expansion tank.

⚠️ Common Signs of Failure

• Air remains trapped in the cooling system
• Engine temperature fluctuates
• Pipe blockage or corrosion
• Repeated coolant loss from poor deaeration

🛠️ Service Notes

• A vent line must run continuously uphill to its high point with no dips or sags that can trap fluid, or the system will not self-vent
• Check that the bore and any restriction or fitting at each end is completely clear; these lines block with scale and debris, and the symptom is persistent air in the system
• Renew the seals, unions and clips, route the pipe clear of hot and moving parts, and support it so it cannot chafe or fatigue
• Do not kink or sharply bend the pipe, force it into place, or substitute a different length or bore
• Refill, vent and run up, then check the joints for weeping and confirm the system holds pressure

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 21505623 → Supersedes 21403338 → Supersedes 21139817

OEM / Related Numbers

• 21403338 earlier number superseded by this part
• 21139817 earlier number superseded by this part
• 21504807 - expansion-tank coolant pipe
• 21139808 - related air-vent pipe
• 21381313 - water pipe

📦 Condition

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