Parts for your 2009 Subaru Impreza-Coolant

2009 Subaru Impreza Coolant — What It Does and How to Look After It

Coolant is absolutely relevant and used on the 2009 Subaru Impreza. Subaru’s own technical literature confirms it: the 2009 Impreza Owner’s Manual specifies genuine Subaru engine coolant, and Subaru’s technical bulletin introducing “Subaru Super Coolant” (the blue, long‑life coolant used on late‑2000s models) details its extended service life and chemistry. Together, these sources establish that the Impreza’s EJ-series engines rely on ethylene glycol, phosphate‑type, silicate‑free coolant, premixed 50/50.

On this Impreza, coolant does the heavy lifting of carrying heat away from the engine, keeping temperatures steady in Aussie heat and chilly Kiwi winters. It also raises the boiling point, prevents freezing, fights corrosion inside alloy components, and lubricates the water pump. Subaru’s long‑life “Super Coolant” (blue) is designed to protect the system for years without forming scale or gunk.

For service planning, Subaru’s guidance for blue Super Coolant is an extended initial interval that can be up to around 11 years or 220,000 km from factory fill, then periodic changes thereafter. If service history is unknown, testing the coolant or replacing it earlier is smart practice. Mixing different coolant chemistries cuts that long life short, so sticking with genuine Subaru Super Coolant (or an exact equivalent: phosphate HOAT, silicate‑ and borate‑free) is the safe bet.

• Check the translucent expansion tank when the engine is cold, the level should sit between the marks and the colour should remain clean blue, not rusty or milky.
• Inspect hoses, clamps and the radiator cap, perished rubber or a tired cap can cause slow losses and hot running.
• If coolant is replaced, bleed the system properly with the heater on full hot to purge air pockets, then recheck the level after the first drive.
• Never mix tap water into concentrate, use demineralised water if a premix isn’t used. Dispose of old coolant responsibly.

Warning signs that attention’s due include temperature fluctuations, sweet smells, visible leaks, discoloured coolant, or the radiator fans running more than usual. With the right coolant and basic checks, a 2009 Impreza stays happy on long climbs, summer commutes and weekend getaways alike.

Popular questions

What coolant type does a 2009 Subaru Impreza use?
Subaru specifies a phosphate‑based, ethylene glycol, silicate‑free long‑life coolant. Genuine Subaru Super Coolant (blue, premixed 50/50) matches the chemistry and service life recommended in the 2009 Impreza Owner’s Manual and Subaru’s coolant bulletin.

How often should the coolant be changed?
With Subaru Super Coolant, the factory fill can last up to about 11 years or 220,000 km, with subsequent changes at extended intervals. Severe duty, unknown history, or mixed coolants justify earlier replacement.

Can green “universal” coolant be mixed with Subaru’s blue coolant?
Not recommended. Mixing can shorten service life and reduce corrosion protection. If mixing has occurred, treat the system as conventional and replace earlier, ideally after a thorough flush.