The correct coolant is Subaru Genuine Long-Life Coolant Type D or an equivalent silicate-free, ethylene glycol–based coolant designed for Subaru engines; it is typically used as a 50/50 premixed solution or mixed 50/50 with distilled water if you purchase concentrate.
For a 2017 Forester, Subaru specifies a long-life, aluminum-safe coolant that matches the vehicle’s cooling system requirements. Using the wrong type can lead to corrosion, overheating, or printer-related issues with seals and hoses. Always verify the specification in your owner’s manual or with a Subaru dealer if you’re unsure about compatibility. Do not mix different coolant chemistries unless the packaging explicitly confirms compatibility.
Coolant Options for the 2017 Forester
Below are the practical options you can consider when selecting coolant for your Forester. Each option meets common Subaru guidance, but always confirm compatibility on the label or with a mechanic.
- Subaru Genuine Long-Life Coolant Type D (Genuine Subaru). A factory-approved, silicate-free, ethylene glycol–based coolant designed for Subaru engines; available premixed or as concentrate to be mixed to 50/50.
- High-quality aftermarket coolant labeled as compatible with Subaru engines (silicate-free, ethylene glycol–based, and using Organic Acid Technology). Look for packaging that explicitly states Subaru compatibility or OEM-grade specifications (e.g., meets or exceeds D3306 or Subaru requirements).
Using a coolant that is specifically marked as compatible with Subaru or that meets the vehicle’s OEM specification helps protect the cooling system and maintains warranty coverage. If unsure, consult your dealership or a qualified mechanic.
Mixing and Maintenance Tips
Before you proceed with mixing or a coolant service, here are guidelines to help ensure a proper fill and long service life.
- Ensure the engine is completely cool before opening the cooling system to avoid burns or pressure release.
- If you purchase concentrate, mix it 50/50 with distilled water before pouring into the system. Premixed coolant is ready to use as-is.
- Only use silicate-free, ethylene glycol–based coolant designed for Subaru engines. Do not mix different types of coolant unless the manufacturer explicitly allows it.
- Bleed the cooling system if your model requires it, refill to the proper level, and check for leaks after starting the engine and warming up to operating temperature.
After completing the fill, recheck coolant level when the engine has cooled again and monitor for any temperature or leakage issues in the days following the service.
Summary
For a 2017 Subaru Forester, the safest choice is Subaru Genuine Long-Life Coolant Type D or an equivalent silicate-free, ethylene glycol–based coolant labeled compatible with Subaru engines. Use a 50/50 mix (premixed or concentrate with distilled water) and follow the owner’s manual guidance for bleeding and refilling. Always verify compatibility on the product packaging or with a dealer to protect the cooling system and maintain vehicle reliability.