What type of coolant for Subaru?
Subaru typically requires an ethylene glycol–based, silicate-free long‑life coolant—best to use Subaru Genuine Long-Life Coolant (or any coolant explicitly labeled Subaru-compatible), premixed at a 50/50 ratio with distilled water.
Understanding Subaru's coolant requirements
Subaru's cooling system is built around a specific chemical formulation that protects aluminum components and the radiator. Using a coolant with silicates or phosphates, or a product not approved by Subaru, can lead to corrosion, gasket damage or overheating. Always refer to the owner's manual or a dealership for the exact specification for your model year and market.
What to look for in a coolant
Before listing the practical options, note these criteria that help ensure compatibility with Subaru engines.
- Ethylene glycol-based formulation designed for automotive use
- Silicate-free and phosphate-free or employing HOAT/OAT chemistry suitable for aluminum engines
- Explicitly labeled as Subaru-compatible or Subaru Genuine Long-Life Coolant
- Available as premixed (50/50 with distilled water) or as a concentrate that you mix to 50/50
- Avoid universal coolants that do not state Subaru compatibility
Using the right coolant helps maintain cooling efficiency and protects the aluminum components common in Subaru engines. Always verify the product data sheet or packaging for Subaru compatibility and the recommended concentration.
Mixing, application, and maintenance tips
Here's how to apply coolant correctly and keep your system in good condition:
- Choose premixed coolant if you want a simple 50/50 solution and to minimize mixing errors.
- If you buy concentrate, mix it with distilled water to achieve a 50/50 solution, unless the label specifies a different ratio.
- Never mix coolant types unless the manufacturer explicitly allows it for Subaru engines.
- Follow the maintenance schedule printed in your owner's manual for coolant replacement; many Subaru models call for a change around 100,000 miles (approximately 160,000 km) or 8–10 years, depending on climate and driving conditions.
After following these steps, you should have a cooling system that maintains proper temperature and corrosion resistance. If in doubt, consult a Subaru-certified technician.
Summary
For Subaru vehicles, the safest path is to use an ethylene glycol-based, silicate-free long-life coolant that is Subaru-compatible, preferably Subaru Genuine Long-Life Coolant. Whether you choose premixed or concentrate, ensure the product is rated for Subaru engines and follow the manual for mixing ratios and replacement intervals. Maintaining the correct coolant type and concentration helps protect aluminum components and prevents overheating, prolonging engine life.
