Coolant should be added to the expansion (overflow) reservoir rather than directly to the radiator. Use a 50/50 premixed ethylene glycol coolant approved for Ford vehicles, and always let the engine cool before opening the reservoir cap.
Understanding the cooling system in the 2015 Fusion
The Fusion uses a closed cooling system with a pressurized expansion tank. The radiator cap is not typically user-serviceable; you fill through the reservoir, and the level should stay between the MIN and MAX marks when the engine is cold. Overheating or leaks require inspection.
Where to locate the coolant reservoir
The expansion tank is a translucent plastic reservoir in the engine bay, usually on the passenger side near the radiator. It has a cap labeled Engine Coolant and MIN/MAX indicators on the side. You check the level with the cap in place only when cold.
How to check and add coolant
Follow this quick checklist to verify the level and top off if needed.
- Park on level ground and allow the engine to cool completely (waiting at least 30 minutes is recommended).
- Clean the reservoir cap area to prevent dirt from entering the system, then slowly remove the cap if the engine is cool.
- Check the coolant level against the MIN and MAX marks on the reservoir. If it is between marks, no action is needed.
- If below the MIN line, add a 50/50 premixed coolant that is compatible with Ford vehicles, pouring slowly to avoid spills and stopping at the MAX line.
- Reinstall the cap securely, start the engine, and monitor for leaks or overheating; recheck the level once the engine cools again and adjust if necessary.
Conclusion: The expansion reservoir is the proper point to add coolant on a 2015 Ford Fusion. If you notice frequent top-offs or overheating, have the cooling system inspected for leaks, a bad cap, or a failing water pump.
What coolant to use and how to mix
Using the correct coolant protects the engine, prevents corrosion, and maintains proper freezing/boiling protection. For the 2015 Fusion, use a high-quality ethylene glycol-based coolant that is explicitly approved for Ford vehicles, typically sold as a 50/50 premixed solution. Do not mix brands unless the label confirms compatibility, and avoid straight concentrate.
- Prefer a Ford-approved coolant such as Motorcraft or an equivalent product labeled compatible with Ford cooling systems.
- Use a 50/50 premixed solution or mix according to the label with distilled water; avoid using tap water that may contain minerals.
- Check the coolant label for system compatibility with aluminum components and overall extended-life performance.
- Do not mix coolants with different chemistries unless explicitly stated as compatible.
Conclusion: Selecting the right coolant is essential for long-term reliability; if you’re unsure, consult your owner's manual or a qualified mechanic before refilling.
Safety reminders
Working with the cooling system can cause burns from hot coolant or steam. Always let the engine cool, wear protective gear, and never open the reservoir cap if it’s hot. Keep pets and children away from the engine bay while performing maintenance.
Summary
To replenish coolant in a 2015 Ford Fusion, add through the translucent expansion reservoir to the MAX line when the engine is cold, using a 50/50 premixed coolant approved for Ford. Do not add coolant directly to the radiator or when the engine is hot, and consult the owner's manual for exact specification and procedure.