21185610 Expansion Plug | Genuine Volvo Penta Part

🔧 Product Description

Genuine expansion or core plug used to close a machined or cast opening in the Volvo Penta engine assembly that specifies part number 21185610. The plug must match the original diameter, depth and installation method.

⚙️ Key Features

• Genuine Volvo Penta expansion plug
• Factory diameter and material
• Closes a block, head or housing opening
• Designed for the assigned coolant or oil environment

🔌 Function

The expansion plug seals the casting or machining opening and prevents fluid leakage.

⚠️ Common Signs of Failure

• Coolant or oil seepage around the plug
• Corrosion or perforation
• Plug displaced from the bore
• Leakage after freezing or overheating

🛠️ Service Notes

• Clean the bore out to bare, sound metal and check it for corrosion, pitting or a raised lip — a plug will not seal in a wasted or scored bore, and that bore may need attention first
• Fit the plug square to the bore and drive it evenly with a tool or socket that bears on the correct part of the plug, to the depth the manual specifies; driven in cocked or too deep it will leak
• Seal it with a sealant of the type specified for that joint, not with a silicone or rubbery compound, which is slippery and lets a plug creep out under pressure
• With an expanding rubber type, seat it fully, then tighten the centre nut to expand it against the bore and check it again after the first heat cycle
• Fill, pressure-test or run the system and check the plug for weeping before closing up access, since many of these sit where you cannot see them once the engine is back together

🔄 Supersession & Cross Reference

OEM Supersession Chain

• 21185610 → Supersedes 3580477

OEM / Related Numbers

• 3580477 earlier number superseded by this part

📦 Condition

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