Mercury MerCruiser OEM Oil Filter Adapter Seal 862957 | Remote Oil System | 496 8.1L 8.2L Big Block
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Mercury MerCruiser OEM Oil Filter Adapter Seal — Part 862957
- Part Number: 862957
- Full Catalog Number: 26-862957
- Brand: Mercury Marine / MerCruiser (Genuine OEM)
- Official Product Type: Engine Lubrication — Oil Filter Adapter Seal
- System: Engine lubrication — remote oil filter / oil cooler adapter sealing
- Diagram Position: Oil filter adapter seal at oil filter adapter 862870T in the remote oil system diagram
- Used With: Oil filter adapter 862870T
- GTIN / UPC: 745061462038
- Qty Required: 1 per applicable assembly
- Weight: approx. 0.01 kg
Note: This seal belongs specifically to the remote oil filter adapter assembly, not to the spin-on oil filter itself. If oil is appearing around the remote filter plumbing, inspect 862957 together with the nearby swivel-tube seal (42077) and the oil hoses before reassembling the system.
What It Does
The 862957 is the genuine OEM oil filter adapter seal used in the remote oil system on select MerCruiser big-block gasoline engines. It seals the connection at the oil filter adapter, preventing engine-oil leakage where the remote filter plumbing interfaces with the adapter assembly. Mercury parts diagrams place 862957 directly with oil filter adapter 862870T in the remote oil system. Because this is a compressed oil-system seal, it should be replaced whenever the adapter joint is opened — a previously compressed seal will not reseal reliably after being disturbed.
Compatible Applications
Confirm fitment by engine serial number and the specific MerCruiser remote oil system diagram before ordering. Not every 496, 8.1L, or 8.2L installation uses the same remote-oil configuration.
- MerCruiser 496 MAG — selected remote oil system configurations
- MerCruiser 496 MAG H.O. — selected configurations
- MerCruiser 496 MAG EC — selected configurations
- MerCruiser 496 MAG H.O. EC — selected configurations
- MerCruiser 496 H.O. Plus Series — selected configurations
- MerCruiser 8.1L Inboard — selected configurations
- MerCruiser 8.1L Inboard H.O. — selected configurations
- MerCruiser 8.1L Inboard EC — selected configurations
- MerCruiser 8.1L TowSport MPI — selected configurations
- MerCruiser 8.1L Plus Series — selected configurations
- MerCruiser 8.2 MAG — selected configurations
- MerCruiser 8.2 MAG H.O. — selected configurations
- MerCruiser 8.2 MAG EC — selected configurations
- MerCruiser 8.2 MAG H.O. EC — selected configurations
- MerCruiser 8.2L Horizon / Inboard — selected configurations
- MerCruiser 520 HP — selected configurations
- MerCruiser 540 HP — selected configurations
Not sure it fits? Send us your MerCruiser engine serial number before ordering.
Related Remote Oil System Components
Mercury remote oil system diagrams show 862957 alongside the following components. Inspect all seals, hoses, and fittings while the adapter assembly is apart — these are sold separately and are not included with 862957:
- 862870T — Oil filter adapter (the primary component 862957 seals at)
- 862958 — Oil filter adapter fitting
- 42077 — Swivel tube seal (inspect together with 862957 during remote oil service)
- 806328 — Oil adapter fitting
- 863899 — Oil hose, filter to adapter
- 863900 — Oil hose, filter to cooler
- 863915 — Oil hose, cooler to adapter
- 863904T — Oil cooler
- 863905T — Oil cooler bracket
Part Numbers
- 862957 — Mercury Marine OEM part number
- 26-862957 — Full Mercury catalog number
No separate confirmed superseding Mercury part number. Order 862957 / 26-862957.
When to Replace
Replace the oil filter adapter seal when:
- Engine oil is leaking around the remote oil filter adapter
- The oil filter adapter (862870T) is removed for any reason
- The existing seal is flattened, hardened, or damaged on inspection
- Oil cooler or remote oil hose service requires disassembly of the adapter
- Seepage is found at the adapter sealing surfaces during an oil-system inspection
Service Interval
Inspect the oil filter adapter seal at each remote oil system service and whenever the adapter is disturbed. Replace the seal any time the adapter joint is opened — a previously compressed seal will not reseal reliably after being disturbed. When diagnosing an oil leak around the remote filter assembly on a 496, 8.1L, or 8.2L engine, inspect 862957 together with the swivel tube seal (42077) and all oil hoses in the remote system before reassembly, since hoses and seals on these systems age together and multiple leak points are common.
Installation Notes
- Confirm 862957 is shown at the correct location in the Mercury remote oil system diagram for your engine serial number before installing
- Clean all adapter sealing surfaces thoroughly before fitting the replacement seal
- Inspect the oil filter adapter (862870T) and fitting (862958) for scoring, corrosion, or thread damage
- Inspect the swivel tube seal (42077) and replace if hardened or damaged — both seals are in the same area and should be addressed at the same time
- Inspect all remote oil hoses for age, cracking, or seepage and replace any that show deterioration
- Replace any other disturbed O-rings or seals in the remote oil assembly
- Follow the applicable MerCruiser service procedure for adapter installation torque and sequence
- Check for oil leaks carefully after startup before returning the engine to service
Technical FAQ
Q: Is this the seal for the spin-on oil filter or for the remote adapter?
This is the seal for the remote oil filter adapter (862870T), not for the spin-on filter itself. It seals the adapter connection in the remote oil plumbing system used on select 496, 8.1L, and 8.2L MerCruiser big-block engines. If you are looking for a spin-on oil filter gasket, that is a different part.
Q: Do I need to replace this seal every time I change the remote oil filter?
Not every filter change requires removing the adapter — the 862957 seals the adapter itself, not the filter canister. However, if the adapter is disturbed during service, the seal should be replaced. Inspect the adapter area for seepage at each oil change.
Q: My 8.1L MerCruiser has an oil leak around the remote filter area — is this the only seal I need?
Possibly not. The remote oil system on 496, 8.1L, and 8.2L engines also uses a swivel tube seal (42077) and multiple oil hoses. If oil is appearing around the remote filter plumbing, inspect all the seals and hoses in the system together before reassembling — multiple seals are often the same age and may be leaking at more than one point.
Q: Does every 496 or 8.1L engine use this remote oil system?
No. Not every 496, 8.1L, or 8.2L installation uses the same remote-oil filter configuration. Confirm that 862957 appears in the remote oil system diagram for your specific engine serial number before ordering.
Parts Desk Insights
The key distinction with 862957 is that it is the remote oil filter adapter seal, not the spin-on oil filter gasket. Customers sometimes confuse the two when diagnosing a leak on a 496 or 8.1L big-block. If oil is showing up around the remote filter plumbing, it is worth pulling the whole system and inspecting 862957 alongside the swivel tube seal (42077) and the oil hoses — on these engines the hoses and seals are typically the same age, and addressing them together avoids returning to the same job for a hose failure a few months later.
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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