Sierra 18-7879-1 Oil Filter – GM/Chevy V6

Sierra 18-7879-1 Oil Filter – GM/Chevy V6

Part Number: 18-7879-1  |  SKU: 47-78791  |  UPC: 808282359829

The Sierra 18-7879-1 is a marine spin-on oil filter designed for GM/Chevy V6 marine engines, including compatible MerCruiser, OMC, and Volvo Penta inboard and sterndrive applications. It uses an 18 mm x 1.5 metric thread — the key differentiator from other Sierra GM marine filters — along with high-efficiency filter media, an anti-drain-back valve, and an epoxy-coated heavy-wall steel canister for corrosion resistance in marine environments.

Key Specifications

• Thread: 18 mm x 1.5 (metric)
• Height: approximately 3.46 in.
• Anti-drain-back valve: Yes
• Canister: Heavy-wall epoxy-coated steel
• Filter media: High-efficiency, meets or exceeds OEM specification

Compatible Applications

• GM/Chevy 3.8L V6 marine inboard engines in MerCruiser, OMC, and Volvo Penta installations
• GM/Chevy 4.3L V6 marine inboard and sterndrive engines in MerCruiser, OMC, and Volvo Penta installations
• Other GM V6 marine applications using a direct-mount 18 mm x 1.5 threaded oil filter

Fitment Note: Confirm your engine model, serial number, and existing oil filter part number before ordering. Some GM V6 marine engines use a remote oil-filter arrangement that requires a different filter. The 18 mm x 1.5 thread is specific to the GM V6 family — do not confuse with the 13/16"-16 thread used on GM V8 marine applications.

Service Interval

Replace at every engine oil change. Follow the engine manufacturer’s recommended service interval — typically every 100 hours of operation or once per season, whichever comes first.

Installation Notes

• Remove the old filter and confirm the old gasket has come away with it — a retained gasket will cause an oil leak
• Clean the filter mounting surface
• Lightly coat the new filter gasket with fresh engine oil before threading it on
• Tighten by hand plus ¾ turn, or per engine manufacturer specification — do not over-tighten
• Run the engine and inspect for leaks before returning to service

OEM & Cross-Reference Part Numbers

• Sierra: 18-7879-1
• MerCruiser: 35-802884, 35-802884Q, 35-802884T, 35-883702K, 41815
• Quicksilver: 35-883702Q
• OMC: 173834, 502903
• Volvo Penta: 841750
• Chrysler: L-319
• Mallory: 9-57803
• EMP: 35-57803
• Wix: 51036
• Fram: PH3980

Related Products

• Sierra 18-7876-1 Oil Filter – GM/Chevy Long — long-style 13/16"-16 GM V8 marine filter
• Sierra 78242 Oil Filter – GM/Chev Short — short-style GM marine filter
• Sierra 18-7878-1 Oil Filter – Ford/Chrysler/Volvo Short
• Sierra 18-7824-2 Marine Oil Filter – GM MerCruiser, Volvo Penta, OMC, Crusader & Indmar
• Sierra Oil Drain Kit – 1/2"-20 Thread, 42" Length (47-7891)

Parts Desk Insights

Best Use Case: Routine oil and filter changes on GM/Chevy V6-powered MerCruiser, OMC, and Volvo Penta marine engines. The 3.8L and 4.3L GM V6 is one of the most common sterndrive engine families, and this is its direct-mount filter. It’s a frequently reordered maintenance part — customers with 4.3L MerCruiser packages will encounter this filter regularly.

Common Issues: The most common fitment mistake is confusing this 18 mm x 1.5 metric-thread filter with the 13/16"-16 threaded filters used on GM V8 marine engines. If a customer is unsure, the fastest confirmation is to match MerCruiser 35-802884, OMC 173834, or Volvo Penta 841750 against what’s on their engine. Also remind customers to check whether their engine uses a direct-mount or remote filter arrangement — V6 engines with remote mounts use a different filter entirely.