Water Drain Distribution Housing – Fits Mercury MerCruiser 4.3L 5.0L 5.7L 6.2L Engines (Replaces 863444T1, 863444A1, 863444T2)

Water Drain Distribution Housing – Fits Mercury MerCruiser 4.3L, 5.0L, 5.7L, & 6.2L Engines

This water drain distribution housing is a direct-fit replacement for a range of Mercury MerCruiser engines. It is designed for 262 CID (4.3L), 305 CID (5.0L), 350 CID (5.7L), and 377 CID (6.2L) V6 and V8 models from 1998 and newer, including 350, 377, and 383 MAG MPI variants.

This assembly directly replaces Mercury MerCruiser OEM part numbers: 863444T1, 863444A1, 863444T2, and 863631T1.

• Engine compatibility: V6 & V8 marine engines (1998+)
• Installation type: Direct replacement with manual drain plugs
• Package includes: 1x Housing, 2x Drain Plugs, 2x O-Rings

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 x Water Distribution Housing
• 2 x Manual Drain Plugs
• 2 x O-Rings

Installation Guide

1. Safety First: Ensure the engine is off and cool. Disconnect the negative battery terminal.
2. Drain Coolant: Place a catch pan under the engine and open the drain plugs to empty the cooling system.
3. Remove Old Housing: Carefully disconnect any hoses attached to the housing and unbolt it from the engine block.
4. Clean Surface: Thoroughly clean the mounting surface on the engine block, removing any old gasket material or sealant.
5. Install New Housing: Place the new O-rings on the new distribution housing. Mount the housing and tighten the bolts to the manufacturer's recommended torque specifications.
6. Reconnect & Refill: Re-attach any hoses and install the new drain plugs. Refill the cooling system with the appropriate coolant.
7. Final Checks: Reconnect the battery terminal. Start the engine and let it run for several minutes, carefully checking for any leaks around the new housing.

Troubleshooting & FAQ

How do I confirm this fits my engine?
This housing fits MerCruiser V6 and V8 engines (4.3L, 5.0L, 5.7L, 6.2L) from 1998 and newer. To ensure a perfect match, please review the detailed "Compatible Engine Models" table and verify that your model is listed. Cross-referencing your original part number with the numbers on our list (e.g., 863444T1) is the best way to confirm fitment.

What are the signs that my water distribution housing is failing?
Common signs of failure include visible coolant leaks from the housing body or its seals, cracks in the material, persistent engine overheating issues, or difficulty using the drain plugs for winterization.

Is this housing a direct replacement for the original?
Yes, this is an aftermarket part engineered to be a direct-fit replacement. It matches OEM specifications for size, mounting points, and function to ensure a straightforward installation without modifications.

OEM vs. Aftermarket?
This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

How fast do you ship and how much does it cost?
We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

What is your warranty and return policy?
This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.