Quicksilver MerCruiser Replacement Thermostat 140°F — OEM-grade engine cooling control

The Quicksilver 8M0089715 is a 140°F replacement thermostat engineered for MerCruiser sterndrive engines that use standard cooling systems.

Keeping your marine engine at the correct operating temperature is essential for reliable performance and long life. The Quicksilver 8M0089715 thermostat is an OEM-grade replacement part designed to restore proper coolant flow and temperature regulation in compatible MerCruiser sterndrive applications. Quicksilver — a long-established supplier to Mercury Marine and other powersports brands — produces this part to the same design and testing standards used in original equipment, helping you maintain factory-caliber cooling control.

How will this 140°F thermostat affect engine performance?

Installing the correct temperature thermostat helps the engine reach and hold its optimal operating temperature quickly and consistently. That supports fuel efficiency, reduces excessive wear caused by overcooling, and helps the engine deliver intended power under load.

• Targets 140°F to stabilize coolant temperature
• Prevents prolonged cold-running conditions that reduce efficiency
• Helps maintain designed combustion and emissions characteristics
• Restores factory thermal control when the original thermostat fails

Which MerCruiser models use part 8M0089715 and how do I confirm fit?

This replacement matches the cooling specification for a range of MerCruiser sterndrive engines that call for a 140°F thermostat. Always verify compatibility by consulting your boat’s owner’s manual, service manual, or parts catalog to ensure correct application.

• Check the engine model and serial number against your manual
• Confirm the specified thermostat temperature is 140°F
• Contact an authorized dealer if you’re unsure about fitment details

How simple is installation and what tools are required?

Replacement is straightforward for anyone with basic mechanical skills and common shop tools. Typical removal of a failed thermostat and installing the new unit can be performed with hand tools, but follow the instructions in your engine’s service manual for proper procedure and torque values.

• Requires standard hand tools (wrenches, screwdrivers) for most installations
• Follow manufacturer's removal and installation steps to avoid leaks
• Inspect gaskets, seals, and coolant after installation

What materials and quality standards back this Quicksilver part?

Quicksilver parts are engineered for marine use and subjected to rigorous testing to meet original equipment expectations. This thermostat is built to withstand the thermal cycles and operating environments common to sterndrive cooling systems.

• Manufactured to OEM design and performance standards
• Tested for durability in marine cooling conditions
• Supports factory-level performance and protection

Who is this for? The Quicksilver 8M0089715 thermostat is aimed at boat owners, marine technicians, and service shops who maintain MerCruiser sterndrive engines that specify a 140°F thermostat. It’s suitable for anyone seeking an OEM-quality replacement to restore proper engine temperature control — from DIY owners comfortable with basic repairs to professionals performing scheduled maintenance. Before you buy, confirm the thermostat temperature and part number in your owner’s or service manual to ensure proper fit.

Features:

• 140°F thermostat
• Use only the temperature thermostat listed in your owner's manual or service manual
• Proper engine cooling temperature ensures peak performance and highest efficiency
• Easy to replace with common shop tools
• See your owner's manual for removal of non-functioning thermostat and replacement of new thermostat