Volvo Penta MD2010 MD2020 MD2030 MD2040 Lubrication System O-Ring 861830
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Part Details
- Part Number: 861830
- Brand: Volvo Penta
- Official Product Type: Lubrication System O-Ring
- Supersedes: No confirmed superseding number on record
- Replaced By: 861830 is the current active part number
- Engine Family: Volvo Penta MD2010, MD2020, MD2030 and MD2040 marine diesel
- System: Engine lubrication — seals the oil-pressure relief valve assembly within the lubrication circuit, adjacent to the engine oil filter and lubrication passages
- Diagram Position: Reference #29 in the applicable MD-series lubrication system schematic; the adjoining oil-pressure relief valve (3583580, supersedes 861829) is reference #28
- Quantity Required: 1 per assembly
- Kit Contents: One O-ring, supplied individually
Compatible Applications
Fitment is engine-model and serial-number specific. Match 861830 against the exact Volvo Penta lubrication system diagram for the engine being serviced. These engines contain several O-rings of similar appearance in the same lubrication system — match by part number and diagram position, not appearance alone.
- MD2010-C • MD2010-D
- MD2020-C • MD2020-D
- MD2030-C • MD2030-D
- MD2040-C • MD2040-D
Serial Number Fitment Notice
Volvo Penta used several different O-rings in the same lubrication system on these engines, including 861851 and 861997. Do not substitute a similar-sized O-ring without confirming the Volvo Penta part number and diagram position. Confirm the complete engine model and serial number before ordering.
Lubrication System Assembly Context
Components shown in the same lubrication system assembly include:
- 3583580 — Oil-pressure relief valve (supersedes 861829) — diagram ref #28
- 861830 — This O-ring — diagram ref #29
- 861473 / 3840525 — Engine oil filter (model-dependent)
- 861825 — Nipple / fitting
- 861850 / 3580297 — Oil tube
- 861851 — Additional lubrication system O-rings
- 861997 — Oil pickup / suction system O-ring
When This Part Needs Replacement
- Oil-pressure relief valve is removed for any reason
- Oil seepage visible around the relief valve installation
- O-ring is flattened or permanently compressed
- Rubber has hardened or become brittle
- Cuts, nicks, or surface damage visible on inspection
- Lubrication system service exposes the original seal
Reusing a compressed or hardened O-ring at reassembly is a reliable cause of an oil leak after service. Replace whenever the assembly is disturbed.
Installation Notes
Clean the relief-valve bore and sealing surface before fitting the new O-ring. Lightly coat the O-ring with clean engine oil to help prevent pinching or tearing during installation. Confirm the O-ring sits evenly in its groove before assembling — a twisted or pinched seal will not seal properly. Inspect the relief valve 3583580 while the assembly is apart. Follow the Volvo Penta service procedure for the correct assembly sequence and torque specification for the specific engine model.
Related Parts
- 3583580 — Oil-pressure relief valve (supersedes 861829)
- 861473 — Engine oil filter (selected MD-series)
- 3840525 — Engine oil filter (selected MD-series)
- 861825 — Nipple / fitting
- 861850 — Oil tube
- 861851 — Lubrication system O-rings
- 861997 — Oil pickup / suction system O-ring
Parts Desk Insight
This O-ring is specifically positioned at the pressure relief valve in the lubrication circuit, which makes the diagram position (#29) the most reliable way to confirm you have the right seal. These MD-series engines have multiple O-rings of similar appearance in the same system — 861830, 861851, and 861997 can all look nearly identical out of context. The relief valve itself (now 3583580, previously 861829) is worth inspecting while the O-ring is being replaced — if the valve is sticking or worn, addressing it at the same service avoids pulling the assembly apart again shortly after.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
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