WLFINKMO water distribution housing for Mercruiser/Mercury 863631T1 replacement with drain plug, fits 4.3L–6.2L V6/V8 engines

WLFINKMO's water distribution housing with drain plug is a direct-fit replacement assembly for many Mercruiser, Mercury and Quicksilver inboard V6 and V8 engines, including models using 4.3L–6.2L and 262–383 CID setups.

This replacement water distribution housing helps route coolant through the engine’s intake and block and includes five manifold engine block drain plugs for simplified servicing. It’s designed to match the fit and function of OEM part numbers 863631T1, 863802T2 and 863444T2 so you can restore proper coolant flow after a leak or when refreshing the cooling system. Before ordering, confirm your machine’s part number and engine configuration to ensure compatibility.

Which engines and model families does this housing work with?

It fits a broad range of Mercury/ Mercruiser/Quicksilver inboard engines. Compatible displacements include 4.3L, 5.0L, 5.7L, 6.2L and larger Mag and Stroker variants spanning 262, 305, 350, 377 and 383 CID for both MPI and Mag applications.

• 4.3L, 5.0L, 5.7L, 6.2L MPI configurations for Alpha and Bravo sterndrives
• 5.7L MPI for MIE and SKI setups
• 350 Mag MPI for Alpha, Bravo, Horizon and MIE installations
• 377 Mag MPI/383 Mag Stroker and 262–383 CID V6/V8 engines

How does this replacement match OEM parts and what’s included?

The housing is manufactured to replace the common OEM numbers listed for this cooling component and comes with the drain hardware needed to seal the manifold ports. It’s intended as a like-for-like service part to restore cooling passages and prevent leaks when the original housing is damaged or corroded.

• Replaces: OEM 863631T1, 863802T2 and 863444T2
• Package contents: 1 water distribution housing plus 5 manifold engine block drain plugs
• Designed for straightforward swap-in using the engine’s existing gaskets and mounting points

What should I check before installing this water distribution housing?

Verify the part number and compare the new housing to your old piece to confirm port locations and bolt patterns match. Also inspect surrounding components—thermostat, hoses and mounting studs—as worn parts can affect sealing and long-term performance.

• Confirm your OEM part number matches 863631T1, 863802T2 or 863444T2
• Compare coolant port and bolt hole alignment visually before installation
• Replace gaskets, thermostat and corroded fasteners during the service for best results

Can I install this myself or should a technician handle it?

Experienced DIYers comfortable with engine cooling systems can install this housing using standard tools, but those unfamiliar with marine engine plumbing should seek professional help. Proper torque, correct gasket placement and leak testing are essential to avoid future coolant loss.

• Requires draining coolant and careful reassembly to factory torque specs
• Leak-test after filling and running the engine to operating temperature
• Professional installation recommended if you lack marine engine experience

Who is this for: This WLFINKMO water distribution housing is aimed at boat owners and marine technicians who need a reliable, OEM-style replacement for common Mercury/Mercruiser/Quicksilver inboard engines (V6 and V8). It’s a practical choice when the original housing is cracked, corroded or begins to leak, and when you want an assembly that includes the manifold drain plugs needed to complete the repair. Always cross-check part numbers and engine models before purchase to ensure a correct match.