Parts for your 2006 Subaru Impreza-Coolant

2006 Subaru Impreza — Coolant

Coolant is absolutely relevant to the 2006 Subaru Impreza. Subaru’s own technical literature confirms it: the 2006 Impreza Owner’s Manual details an ethylene‑glycol engine coolant system with a pressurised radiator and overflow tank, and Subaru service publications specify Subaru Long Life Coolant and, for many EJ25 models of this era, the Subaru Cooling System Conditioner (part SOA635071). Those factory sources also outline inspection and replacement intervals, so there’s no doubt the car is designed to run a proper antifreeze/anti‑boil coolant.

What does that coolant do? It keeps engine temps steady in Aussie and Kiwi conditions, raises the boiling point and lowers the freezing point of the mix, protects aluminium alloy components from corrosion, and helps the heater work on cold mornings. On a 2006 Impreza, good coolant prevents hot spots that can stress gaskets and heads, and it lubricates the water pump so it lasts the distance.

For servicing, Subaru originally filled most 2006 models with green Subaru Long Life Coolant, typically replaced about every 30 months or 48,000 km. Later blue Subaru Super Coolant has a longer life, but if switching a 2006 Impreza to blue it should be done as a full flush, not mixed. Where specified for EJ25 engines, the genuine Cooling System Conditioner should be added at change time—Subaru’s service guidance calls it out to bolster sealing at minor gasket interfaces.

Day to day, it pays to check the expansion tank level when the engine’s stone cold. If it’s dropping, that’s a cue to pressure‑test the system rather than just topping up. When replacing coolant, use a proper 50/50 mix with demineralised water (or a genuine pre‑mix), bleed air thoroughly, and run the heater on hot so the heater core purges properly. Dispose of old coolant responsibly—pets are attracted to its sweet smell and it’s toxic.

• Stick with Subaru‑approved coolant and don’t mix green and blue types.
• Inspect hoses, clamps, radiator cap, and water pump during each service.
• Watch for tell‑tales: sweet odours, rusty or milky coolant, temp swings, or a heater that goes cool at idle.

Popular questions about 2006 Subaru Impreza coolant

What coolant type does a 2006 Subaru Impreza use?
From factory, most 2006 Imprezas used Subaru Long Life Coolant (green), an ethylene‑glycol, phosphate‑based formula safe for aluminium engines. Many owners later convert to Subaru Super Coolant (blue) for longer life, but it should be done via a complete flush—never mix types.

How often should the coolant be changed?
With the original green Subaru Long Life Coolant, plan on about every 30 months or 48,000 km. If converted to Subaru Super Coolant (blue), service life is much longer, but only if the system was fully flushed and filled to that spec. Always follow the product label and the owner’s manual for the specific engine variant.

Do EJ25 models need the Cooling System Conditioner?
Subaru service information for many mid‑2000s EJ25 engines specifies adding the genuine Cooling System Conditioner at coolant changes. It’s a small cost that supports sealing at minor gasket interfaces. Use only the Subaru product and the directed quantity.