WLFINKMO Water Distribution Housing for Mercury MerCruiser 4.3–6.2L with 5 Drain Plugs — Direct OE Fit

WLFINKMO's water distribution housing with drain plug is a direct-fit replacement for select Mercury/MerCruiser/Quicksilver V6 and V8 engines, restoring coolant routing and providing five drain plugs for reliable maintenance.

Designed to match OE mounting points and coolant passages, this water distribution housing replaces part numbers 863631T1, 863802T2, and 863444T2 across a range of MerCruiser, Mercury and Quicksilver inboard engines. It suits MPI and Mag applications including 4.3L, 5.0L, 5.7L, 6.2L, and a number of CID V6/V8 variants used in Alpha and Bravo sterndrive configurations. The kit includes one housing and five manifold drain plugs so you can reseal and drain the engine block as needed during service.

Which engines and models will this housing fit?

This housing is compatible with a broad set of Mercury/Mariner/MerCruiser applications. It is intended for MPI and Mag engine families and covers common displacement and CID variants used in Alpha and Bravo drive systems.

• Supports 4.3L, 5.0L, 5.7L (MPI, MIE, SKI variants), and 6.2L MPI engines.
• Covers 262, 305, 350, 377, 383 CID engines; V6 and V8 configurations.
• Fits Mag and MPI versions for Alpha, Bravo and Horizon sterndrives where OE part numbers match.
• Replaceable with OE numbers 863631T1, 863802T2, 863444T2 when part cross-references match.

How do I verify fitment before ordering?

Confirming fitment reduces returns and installation headaches. Compare the OE number stamped on your current housing to the replacement part numbers and check engine displacement and drive type.

• Inspect your current housing for the OE number and compare to 863631T1 / 863802T2 / 863444T2.
• Match engine displacement (4.3, 5.0, 5.7, 6.2, 262–383 CID) and MPI/Mag designation.
• Verify sterndrive type (Alpha, Bravo, Horizon) and V6/V8 layout in your service manual.
• Contact the seller with your engine serial number if unsure before purchase.

What comes in the box and what tools or additional parts are typically needed?

The package ships with the housing plus five manifold engine block drain plugs to replace worn or missing plugs during reassembly. You’ll likely need basic hand tools and new gaskets or sealant for installation.

• Included: 1 × water distribution housing, 5 × manifold block drain plugs.
• Recommended additional parts: new housing gasket, thread sealant, and coolant.
• Tools commonly required: socket set, torque wrench, gasket scraper, coolant catch pan.
• Inspect bolt threads and mating surfaces; replace corroded hardware as needed.

What performance or service benefits can I expect from replacing this housing?

Replacing a cracked, corroded, or leaking water distribution housing restores correct coolant flow and helps prevent overheating and coolant loss. Using the included drain plugs simplifies block draining and reassembly during maintenance.

• Restores sealed coolant passages to reduce leaks around the manifold.
• Provides five new drain plugs for complete block draining and resealing.
• Matches original mounting locations for straightforward installation.
• Helps maintain engine cooling efficiency when installed with proper gaskets.

Who is this for: This water distribution housing is intended for boat owners, marine technicians and restoration specialists working on Mercury/MerCruiser/Quicksilver inboard engines that match the listed displacements and OE numbers. It’s a practical replacement for anyone servicing Alpha or Bravo sterndrive installations who needs a direct-fit housing plus drain plugs to complete a cooling-system repair.