Thermostat Housing Assembly – Fits Mercury Marine 65-150 HP Outboards (Replaces 892864T06, 8M0090819)

Thermostat Housing Assembly – Fits Mercury Marine 65-150 HP Outboards (Replaces 892864T06, 8M0090819)

This thermostat housing assembly is engineered for Mercury Marine 65-150 HP 4-stroke outboard engines from 2006 and newer. It is a complete bolt-on solution for models including the 75, 80, 90, 100, 115, and 150 EFI series, ensuring proper engine temperature regulation.

This assembly is a direct replacement for multiple OEM and aftermarket part numbers, including Mercury 892864T06, 8M0090819, 892864A06, and Sierra 18-3633 and 18-3635.

• Complete Kit: Includes the thermostat, housing, O-ring, and clamp for a full replacement.
• Installation: Designed for a direct bolt-on installation with no modifications required.
• Material: Constructed from marine-grade metal to resist corrosion and ensure durability.

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 Thermostat with housing (replaces 8M0090819)
• 1 x O-ring (replaces 8M005958)
• 1 x Clamp (replaces 888988008)

Installation Guide

1. Safety First: Disconnect the battery and ensure the engine is completely cool before starting.
2. Drain Coolant: Place a drain pan under the engine and carefully drain the cooling system.
3. Locate Housing: Identify the thermostat housing on the engine block.
4. Disconnect Hoses: Loosen the clamp and remove the hose connected to the housing.
5. Remove Old Housing: Unbolt and remove the old thermostat housing assembly. Note the orientation of the parts.
6. Clean Surface: Thoroughly clean the mounting surface on the engine block, removing any old gasket material or sealant.
7. Install New Assembly: Place the new thermostat and O-ring in the new housing and mount it onto the engine block.
8. Secure Bolts: Tighten the bolts evenly and to the manufacturer's recommended torque specifications.
9. Reconnect Hose: Reattach the coolant hose and secure it with the new clamp.
10. Refill Coolant: Refill the cooling system with the appropriate coolant mixture.
11. Check for Leaks: Reconnect the battery, start the engine, and let it warm up. Carefully check for any coolant leaks around the new housing.

Troubleshooting & FAQ

Q: How do I confirm this thermostat housing fits my specific engine? A: The most reliable method is to match your engine's serial number to the ranges provided in the compatibility table. You can use the linked Mercury Serial Number Guide to find your serial number. Cross-referencing the part number (892864T06 or 8M0090819) stamped on your old part also helps ensure a match.

Q: What are the symptoms of a failing thermostat or housing? A: Common signs include engine overheating, engine temperature running too low, erratic temperature gauge readings, visible coolant leaks from the housing, or steam from the engine compartment.

Q: What is the operating temperature of the included thermostat? A: The thermostat in this assembly is rated to open at 122°F (50°C) to ensure your engine reaches its optimal operating temperature quickly and maintains it consistently.

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.