Parts for your 2008 Subaru Forester-Coolant

2008 Subaru Forester coolant — what it does and how to look after it

Coolant absolutely is used on the 2008 Subaru Forester. Technical sources including the 2008 Subaru Forester Owner’s Manual, Subaru factory workshop manuals for the EJ25 boxer engine, and mainstream repair guides all specify a liquid-cooled engine using an ethylene glycol–based coolant. It isn’t optional equipment, it’s fundamental to how the Forester’s engine is designed to run.

In this Forester, coolant circulates through the engine and radiator to hold temperature steady, helping prevent overheating on hot Aussie and Kiwi summer days and guarding against corrosion year-round. The correct coolant mix raises the boiling point, lowers the freezing point, and carries corrosion inhibitors that protect alloy heads, the radiator, heater core and water pump. It also helps lubricate the pump seal, which keeps the system leak-free for longer.

For best results, use Subaru Genuine coolant that meets Subaru’s spec: silicate-free, phosphate-based, ethylene glycol (often seen as Subaru Long Life Coolant in green, or Subaru Super Coolant in blue depending on market and build). Don’t mix types or colours, if switching, do a full flush. Use a 50/50 mix with demineralised water unless the product is sold pre-mixed.

Service intervals depend on what’s in the car. Many 2008 vehicles originally used green long-life coolant that’s typically replaced about every 2 years or 40,000–50,000 km. Later blue “super” coolants can run much longer (up to ~10 years/200,000 km in some schedules), with shorter intervals after the first fill. The smart move is to check the owner’s handbook and the label on the expansion tank or radiator cap, then follow the schedule for the exact coolant type fitted.

When servicing, check the level in the expansion bottle when the engine’s cold and top up with the correct premix. If doing a full change, bleed air carefully—run the heater on hot, use a spill-free funnel, and gently squeeze the upper hose to purge bubbles. Watch for signs of trouble like a sweet smell, rusty or milky fluid, frequent top-ups, or the temp gauge creeping higher than normal.

• Inspect hoses, clamps, and the radiator for leaks or crusty residue.
• Replace the radiator cap and thermostat if they’re ageing or suspect.
• Use only demineralised water for mixing, tap water can cause scale.
• Never open the radiator cap when hot, allow it to cool fully.
• Dispose of old coolant responsibly—it’s toxic to pets and wildlife.

Popular questions about 2008 Subaru Forester coolant

What coolant does a 2008 Subaru Forester use?
Subaru specifies a silicate-free, phosphate-based, ethylene glycol coolant. Depending on market and build, that’ll be Subaru Long Life Coolant (green) or Subaru Super Coolant (blue). Use a 50/50 mix with demineralised water unless the product is premixed, and avoid mixing different types or colours.

How often should the coolant be replaced?
If it’s the older green long-life coolant, plan on about every 2 years or 40,000–50,000 km. If the vehicle has the blue long-life “super” coolant, the first interval can be much longer (often up to ~10 years/200,000 km), with shorter intervals thereafter. Always confirm with the service schedule for your VIN and market.

What are signs of a coolant issue on a 2008 Forester?
A rising temperature gauge under load, a sweet smell after shutdown, low level in the overflow bottle, brown or cloudy coolant, white crust around hose joints, or poor cabin heat can all point to problems. Get it pressure-tested and sorted early to protect the EJ boxer from overheating damage.