Thermostat (160°F/71°C) – Fits MerCruiser 3.0L-7.4L V6/V8 (Replaces 8072522, 807252T2, 8M0109441)

Thermostat (160°F/71°C) – Fits MerCruiser 3.0L-7.4L V6/V8 (Replaces 8072522, 807252T2, 8M0109441)

This marine thermostat is engineered for a wide range of MerCruiser 3.0L to 7.4L GM EFI and carbureted engines from 1987 and newer. It is designed for models equipped with a fresh water (closed) cooling system requiring a 160°F (71°C) thermostat, including both Alpha and Bravo sterndrive configurations.

This component is a direct replacement for multiple MerCruiser, Crusader, and other aftermarket part numbers, ensuring broad compatibility for engine maintenance and repair.

• Operating Temperature: Opens at 160°F (71°C) to regulate engine temperature.
• Cooling System Compatibility: Designed exclusively for fresh water (closed) cooling systems.
• Included Component: Package contains one engine thermostat.

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 MerCruiser 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.

MerCruiser

Crusader

Technical Specifications

Package Contents

• 1 x Thermostat (8M0109441)

Installation Guide

1. Ensure the engine is completely cool and disconnect the battery for safety.
2. Drain the engine coolant from the closed cooling system to a level below the thermostat housing. Place a container underneath to catch the fluid.
3. Locate the thermostat housing. It is typically found where the large coolant hose from the heat exchanger connects to the top of the engine.
4. Carefully remove the bolts that secure the housing cover.
5. Gently tap the housing to break the gasket seal and remove the cover. Do not pry the surfaces apart, as this can cause damage.
6. Lift the old thermostat out of the engine block. Note its orientation to ensure the new one is installed correctly.
7. Thoroughly clean all old gasket material and sealant from both the housing cover and the engine's mating surface.
8. Install the new thermostat, making sure it is seated in the proper direction.
9. Place a new gasket onto the housing surface. If required, apply a thin layer of marine-grade gasket sealant.
10. Re-install the housing cover and tighten the bolts to the manufacturer-specified torque in a crisscross pattern.
11. Refill the cooling system with the correct type and amount of coolant.
12. Once reassembled, start the engine, let it warm up, and carefully check for any leaks around the housing.

Troubleshooting & FAQ

Q: How can I be sure this thermostat fits my engine?
A: The best way to confirm fitment is to check your original part number against the numbers in our Part Number Cross-Reference table. You should also consult the Compatible Engine Models list on this page to ensure your specific model and year are listed.

Q: What temperature is this thermostat rated for?
A: This is a 160°F (71°C) thermostat. It is critical to use the temperature rating specified for your engine to ensure correct operating performance and prevent engine damage.

Q: Can I use this thermostat in a raw water (open) cooling system?
A: No. This thermostat is specifically designed for fresh water (closed) cooling systems only. Using it in a raw water cooled engine can lead to improper engine temperatures.

Q: What are the symptoms of a faulty thermostat?
A: Common signs include the engine overheating (if the thermostat is stuck closed) or the engine failing to reach its normal operating temperature (if it is stuck open). Both conditions can negatively affect engine performance and longevity.

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.