Water Distribution Housing – Fits Mercury MerCruiser 4.3L 5.0L 5.7L 6.2L Engines (Replaces 863631T1, 863444T1)

Water Distribution Housing – Fits Mercury MerCruiser 4.3L 5.0L 5.7L 6.2L Engines (Replaces 863631T1, 863444T1)

This water distribution housing is a direct replacement for various Mercury MerCruiser V6 and V8 engines, including 4.3L, 5.0L, 5.7L, and 6.2L models from 1998 and newer. It is compatible with MAG and MPI variants, providing a reliable solution for your marine engine's cooling system.

It directly replaces Mercury MerCruiser OEM part numbers 863631T1, 863802T2, 863444T1, 863444A1, and 863444T2. This assembly is designed for systems that use manual drain plugs, facilitating easier maintenance and winterization.

• Features manual drain functionality for simplified seasonal servicing.
• Constructed from durable black plastic with reinforced aluminum mounting points.
• Engineered to meet OEM specifications for fit and function in standard cooling systems.

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 (replaces 863631T1)
• 2 x Manual Drain Plugs
• 2 x O-Rings

Installation Guide

1. Safety First: Ensure the engine is cool and disconnect the boat's battery.
2. Drain System: Open the existing drain plugs on the old housing to drain the cooling water from the block.
3. Disconnect Hoses: Carefully loosen the hose clamps and detach all water hoses connected to the housing. Note their positions.
4. Remove Old Housing: Unbolt the mounting hardware securing the housing to the engine block and remove it.
5. Clean Surface: Thoroughly clean the engine block mounting surface to ensure a clean seal.
6. Install New Housing: Position the new O-rings and install the new water distribution housing. Secure it with the original mounting hardware, tightening bolts to the manufacturer's recommended torque.
7. Reconnect Hoses: Attach all hoses to their correct ports on the new housing and tighten the clamps securely.
8. Install Plugs: Screw in the new manual drain plugs.
9. Check for Leaks: Reconnect the battery, start the engine, and let it reach operating temperature. Carefully inspect the housing and all connections for any signs of leaks.

Troubleshooting & FAQ

Q: How do I confirm this part fits my specific engine?
A: The best way is to cross-reference your engine's model, year, and serial number with the detailed compatibility table above. This part is a direct replacement for OEM part numbers 863631T1, 863444T1, and others listed in the description.

Q: What are the symptoms of a failing water distribution housing?
A: Common failure signs include engine overheating, visible cracks or warping on the plastic housing, and coolant leaks from the housing body or its connection points. Regular inspection is recommended.

Q: How is this aftermarket part different from the OEM version?
A: Our aftermarket housing is built to match OEM specifications for fit, form, and function. It is made from high-quality materials and includes manual drain plugs for easy winterization, offering a cost-effective alternative to the original part without sacrificing performance.

Q: Is any special maintenance required for this part?
A: No special maintenance is required, but it should be visually inspected for cracks or leaks during regular engine service intervals. The manual drain plugs should be removed for winterization to prevent freeze damage.

Q: OEM vs. Aftermarket?
A: 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.

Q: How fast do you ship and how much does it cost?
A: 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.

Q: What is your warranty and return policy?
A: 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.