Parts for your 2008 Subaru Impreza-Coolant

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

Coolant is absolutely relevant and fitted to the 2008 Subaru Impreza. Subaru’s own technical publications — the 2008 Owner’s Manual, the workshop/factory service manual, and the Subaru Super Coolant product specification — all describe a pressurised, liquid-cooled engine using ethylene glycol–based long‑life coolant. That system manages engine temperature, protects against corrosion and cavitation, and provides freeze/boil protection suited to Australian and New Zealand conditions.

In this Impreza, coolant circulates through the block, heads, radiator and heater core. Its job is to pull heat away from the combustion chambers, stabilise operating temperature, and prevent hot spots that can trigger pinging or warp alloy components. The anti‑corrosion package in the correct Subaru‑approved coolant also shields the water pump, thermostat, radiator and gaskets, keeping the system clean and leak‑free. Under the bonnet, the coolant even helps deliver reliable cabin heat via the heater core in winter.

Servicing this system isn’t hard, and it pays off. Subaru’s service information for this era specifies long‑life, phosphate OAT “Subaru Super Coolant” (the blue premix). In AU/NZ schedules, that blue coolant typically runs a long initial interval — often up to around 10 years/200,000 km — with subsequent changes about every 5 years/100,000 km. If an earlier green conventional coolant is present, plan on much shorter intervals (about 2 years/50,000 km). Because markets and engines vary, the glovebox manual or a VIN‑based check with a Subaru dealer should be treated as the final word.

• Use the correct type: Subaru Super Coolant (blue) premix, or an equivalent meeting Subaru specifications. Don’t mix blue long‑life with generic green — pick one type and stick with it.
• Check the level only when the engine is cold, top up with the same premix. Look for discolouration, rust flecks, oil sheen, or a sweet smell after shutdown — all are warning signs.
• When replacing, drain, refill slowly, and bleed air with the heater set to hot. A spill‑free funnel helps purge bubbles. Run the engine until the fans cycle, allow to cool, and re‑check the level in the radiator and overflow bottle.
• Inspect hoses, clamps, the radiator cap and the water pump weep hole during each service. Use demineralised water only if mixing from concentrate.

Handled this way, the 2008 Impreza’s cooling system stays stable, quiet and leak‑free, helping the boxer engine deliver the longevity it’s known for.

Popular questions about 2008 Subaru Impreza coolant

Does the 2008 Subaru Impreza definitely use engine coolant?
Yes. Subaru’s 2008 Owner’s Manual and factory service information specify a liquid cooling system using ethylene glycol–based coolant. It’s a critical service fluid, not an optional extra.

What coolant should be used?
Subaru recommends its blue long‑life “Subaru Super Coolant” premix, or an equivalent that meets the same specification. Avoid mixing types, if the car currently has green conventional coolant, fully flush before switching to blue.

How often should the coolant be changed?
With blue Subaru Super Coolant, many AU/NZ schedules allow a long initial interval (around 10 years/200,000 km), then about every 5 years/100,000 km. With older green coolant, plan on roughly 2 years/50,000 km. Always verify against the vehicle’s handbook or a dealer using the VIN.