Thermostat Housing with O-Ring Kit – Fits Mercury Marine Verado 135-400 HP (Replaces 892864T04/8M0174561)

Thermostat Housing with O-Ring Kit – Fits Mercury Marine Verado 135-400 HP (Replaces 892864T04/8M0174561)

This thermostat housing assembly is engineered for a precise fit on a wide range of Mercury Verado outboard engines, including 4-cylinder (L4) and 6-cylinder (L6) models from 135 to 400 horsepower, manufactured from 2004 to the present.

It serves as a direct replacement for Mercury Marine parts 892864T04 and the superseded number 8M0174561, ensuring reliable engine temperature regulation for optimal performance and longevity. This kit is built to meet or exceed original equipment specifications.

• Complete Kit: Includes the thermostat, housing, and necessary O-ring for a full replacement.
• Precise Temperature Control: Features a 140°F (60°C) thermostat to maintain the correct engine operating temperature.
• Durable Construction: Made from a high-strength metal alloy with a brass thermostat mechanism for corrosion resistance in marine environments.

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 Assembly (Replaces 892864T04/8M0174561)
• 1 x O-Ring seal (Replaces 8M005958)
• 1 x Oetiker Clamp (Replaces 888988008) (Note: Included with some kits, but may require separate purchase)

Explosion Diagram

Installation Guide

1. Safety First: Ensure the engine is completely cool and disconnect the battery before starting.
2. Drain Coolant: Partially drain the engine coolant below the level of the thermostat housing to prevent spills.
3. Locate Housing: Identify the thermostat housing on the engine block. It is typically connected to the main coolant hoses.
4. Disconnect Hoses: Loosen the hose clamp and carefully twist and pull the coolant hose off the housing nipple.
5. Remove Old Housing: Unscrew the mounting bolts holding the thermostat housing to the engine.
6. Clean Surface: Thoroughly clean the mounting surface on the engine block, removing any old gasket or sealant residue.
7. Install New Assembly: Place the new O-ring on the housing and install the new thermostat assembly. Tighten the mounting bolts to the manufacturer's recommended torque.
8. Reconnect Hose: Attach the coolant hose to the new housing and secure it with the clamp.
9. Refill and Check: Refill the cooling system with the appropriate coolant. Start the engine and let it warm up, carefully checking for any leaks around the housing.

Troubleshooting & FAQ

Q: How do I confirm this thermostat housing will fit my specific Mercury Verado engine?
A: The best way is to match your engine's serial number to the ranges listed in the "Compatible Engine Models" table above. You can find your serial number on a plate on the engine's transom bracket. When in doubt, use the Mercury Parts Catalog link to visually confirm the part number.

Q: What are the common symptoms of a faulty thermostat that needs replacing?
A: Key signs include the engine overheating at low speeds, the temperature gauge reading higher or lower than normal, or erratic temperature fluctuations. A thermostat stuck open can cause the engine to run too cool, leading to poor performance and fuel economy.

Q: What is the operating temperature of this thermostat?
A: This thermostat is rated to open at 140°F (60°C), which is the standard specification for the listed Mercury Verado models to ensure efficient operation.

Q: Does this kit include the hose clamp?
A: The kit includes the thermostat, housing, and O-ring. While some aftermarket kits bundle the Oetiker clamp, it is not always guaranteed. Please check the "Package Contents" list carefully. You may need to reuse your existing clamp or purchase a new one separately.

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.