Mercury – 140°F Thermostat Kit | For V6 & V8 MerCruiser Engines (1983–2016) | 807252T4

Overview

Reliable engine cooling starts with the right thermostat. The Mercury Marine 807252T4 Thermostat Kit is a 140°F OEM replacement designed for V6 and V8 MerCruiser sterndrive and inboard engines built by General Motors (1983–2016). This kit maintains the correct engine temperature for smooth performance, optimal fuel efficiency, and lasting protection. Whether you’re idling in the marina or pushing your boat hard offshore, this thermostat helps your engine stay cool, consistent, and dependable every time.

Key Features

• Purpose: Regulates cooling system temperature to protect and optimize engine performance.
• Temperature Rating: Opens at 140°F, ideal for standard-cooled V6 and V8 MerCruiser engines.
• Compatibility: Fits GM-built V6 & V8 sterndrive and inboard engines (1983–2016).
• Complete Kit: Includes thermostat, O-rings, and gaskets for a complete replacement.
• Ease of Installation: Installs easily using standard hand tools with no modifications required.

Engine & Boat Compatibility

• V6 and V8 MerCruiser sterndrive and inboard engines built by General Motors (1983–2016)
• For engines equipped with standard cooling systems

Performance & Real-World Benefits

The 807252T4 thermostat is a small but vital part of your cooling system. It ensures your engine warms up quickly, maintains a consistent operating temperature, and prevents overheating or inefficient running. If your thermostat sticks open, your engine may never reach its ideal temperature; if it sticks closed, it can overheat quickly. This OEM replacement solves both problems, restoring smooth, efficient cooling control.

Made from corrosion-resistant materials, it’s built to withstand constant exposure to water, heat, and vibration. Once installed, it helps your engine run cleaner, last longer, and deliver better performance and fuel economy on every trip.

Why Choose Mercury OEM

The Mercury 807252T4 is a genuine Mercury Marine thermostat, built to exact factory standards. Aftermarket thermostats may not open at the correct temperature or may degrade quickly in marine environments.

Mercury OEM thermostats are rigorously tested for temperature accuracy, corrosion resistance, and long-term durability. It’s the same thermostat installed by Mercury technicians and found in new MerCruiser engines, giving you confidence and consistent cooling every season.

FAQ

Q1: What engines does this thermostat fit?
It’s made for GM-built V6 and V8 MerCruiser engines (1983–2016) with standard cooling systems.

Q2: What’s the operating temperature?
This thermostat opens at 140°F, maintaining proper cooling system balance.

Q3: What comes in the kit?
The kit includes the thermostat, O-rings, and multiple gaskets.

Q4: Is installation simple?
Yes — it’s a direct-fit OEM replacement that installs with basic hand tools.

Q5: Why OEM instead of aftermarket?
Because Mercury OEM thermostats are precisely calibrated and built to last in marine environments, ensuring reliable performance every time.