Tech guide · Servicing

Subaru Impreza service guide

A turbo Impreza that is serviced properly will cover huge mileages. One that is not usually ends up with a spun bearing or a failed turbo. This guide sets out what to do and when, for the EJ-engined WRX and STI (classic, New Age, GR and VA STI). Your handbook’s figures come first, but most of us are running older or imported cars with unknown history, so we lean towards the shorter intervals.

At a glance

6,000 miles

Oil and filter every 6,000 miles or 12 months, or every 3,000 if you use the car hard.

Every 2 years

Brake fluid at least every two years, and after every track day.

Check the oil

Low oil is the number one killer of EJ engines. Check it every couple of weeks.

Service intervals

Item	Normal use	Hard use (track days, short trips, high mileage, modified)	Notes
Engine oil and filter	Every 6,000 miles (10,000 km) or 12 months	Every 3,000 miles (5,000 km) or 6 months	Fully synthetic, to the grade in your handbook. Check the level every couple of weeks: EJ turbo engines can use oil between services.
Brake fluid	Every 2 years	Every year, or after every track day	Old fluid absorbs water, boils sooner and corrodes the calipers. Bleed the clutch at the same time.
Gearbox and rear diff oil (manual)	Every 25,000 miles (40,000 km) or 3 years	Every 12,500–20,000 miles or 2 years	Use the gear oil the handbook specifies; the 6-speed STI gearbox and the 5-speed take different quantities.
Air filter	Every 30,000 miles or 3 years	Every year in dusty conditions
Pollen (cabin) filter	Every 1–2 years	Every year for city driving
Spark plugs	Platinum/iridium: 60,000 miles. Copper: 30,000 miles	Shorter if the car is remapped	Use the plug grade for your engine; remapped cars often need a colder plug.
Fuel filter	Pre-2005 cars: every 30,000 miles or 3 years	Every 15,000 miles or 2 years	2005-on cars have an in-tank filter with a much longer interval.
Coolant	Subaru Super Coolant: first change at 11 years, then every 6 years	Every 2–3 years if the type or history is unknown	Do not mix coolant types. Bleed the system properly afterwards to avoid air locks.
Timing belt	See our timing belt guide		An interference engine: a snapped belt wrecks the engine.
Brake hoses	Inspect every service, replace at around 5 years		Cracked or bulging hoses fail the NCT.

Turbo-specific habits that save engines

Warm it up gently. Keep the revs and boost low until the oil (not just the coolant) is warm, which takes several miles.
Let it idle after a hard run. Give the turbo 30–60 seconds before switching off, so oil keeps flowing through the hot bearings.
Watch the oil level. Low oil is the number one cause of EJ bearing failures. Check it on level ground with the engine cold.
Use good fuel. Japanese cars were mapped for 100 RON fuel. Irish 95 RON is lower, so a JDM car may need a remap or a more conservative map. Use 98/99 RON where you can, and get a specialist to check the map on any import.
Keep receipts. A stamped book or a folder of invoices adds real value when you sell.

Just bought one? Do these first

Oil and filter, plugs, air filter
Brake fluid, and gearbox and diff oils
Timing belt, unless there is a dated invoice proving it was done
Coolant, if the history is unknown
A compression test, and a boost and fuelling check (datalog) if the car is modified

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