Subaru Impreza Oil Change: Interval, Type, And Steps

Performing a Subaru Impreza oil change protects your engine and preserves fuel efficiency. Most modern Impreza models feature either the FB20 2.0-liter boxer engine or older EJ-series engines, which require precise oil weights and clean filters to manage internal pressures and heat. Neglecting this routine leads to sludge buildup, reduced lubrication, and premature wear on critical components.

This guide covers exact oil capacities, recommended weights by generation, and a step-by-step DIY procedure. You'll also learn how to reset your maintenance light and troubleshoot common mistakes like stripped drain plugs.

Understanding Your Subaru Impreza Oil Specifications

Subaru engines have unique horizontal boxer layouts where pistons move side-to-side. This design places different thermal and mechanical demands on engine oil compared to standard inline-four cylinders.

Oil Viscosity and Types

Choosing the correct oil depends heavily on your Impreza's model year and engine type:

• 2017 to Present (Gen 5 and Gen 6 - FB20 Engines): These direct-injection engines require 0W-20 full synthetic oil. Synthetic oil flows better at low temperatures during winter starts and maintains film strength under high operating heat.
• 2012 to 2016 (Gen 4 - FB20 Engines): Many models specify 0W-20 synthetic, though some early manuals referenced 5W-30 conventional or synthetic depending on regional climate specs. Always check your under-hood oil cap to confirm.
• 2008 to 2011 and Older (EJ Series Engines): These older port-injection engines typically run on 5W-30 conventional or synthetic oil.

Engine Oil Capacities

Adding the exact volume of oil prevents both oil starvation and crankshaft aeration.

• 2.0L FB20 Engine (2012–Present): Holds approximately 5.1 US quarts (4.8 liters) including the filter.
• 2.5L EJ25 Engine (Older Outback/Impreza Sport/WRX variants): Holds approximately 4.2 to 4.4 US quarts.

Always verify your specific fill level using the dipstick after filling, as residual old oil draining from cooler lines can slightly alter the final volume. You can cross-reference official maintenance schedules on the Subaru Owner Support Site.

Recommended Oil Change Intervals

The old rule of changing oil every 3,000 miles is outdated for modern synthetic formulations, but factory intervals still vary based on how you drive.

• Normal Driving Conditions: Change your oil every 6,000 miles or 6 months, whichever comes first. Normal driving involves steady highway commuting with minimal excessive idling.
• Severe Driving Conditions: Change your oil every 3,000 to 3,750 miles. Subaru defines severe conditions as frequent short trips under 5 miles, driving in extreme dust, towing, or extended idling in heavy city traffic.

Sticking strictly to these intervals prevents oil consumption issues common in higher-mileage boxer engines.

Tools and Materials Needed

Gather these items before sliding under your Impreza:

• 5.1 quarts of 0W-20 or 5W-30 full synthetic oil (matching your specific year)
• OEM Subaru oil filter (such as part numbers 15208AA15A or 15208AA17A)
• New crush washer for the oil drain plug
• 14mm socket and ratchet
• Oil filter wrench (cap style or band style)
• Drain pan and funnel
• Ramps or a hydraulic jack with rated jack stands
• Shop rags and nitrile gloves

Step-by-Step DIY Subaru Impreza Oil Change Procedure

Safety comes first. Never crawl under a car supported solely by a hydraulic jack. Always use solid jack stands on level ground or drive onto secure service ramps.

Step 1: Warm Up and Elevate

Drive your Impreza for five minutes to warm the oil, which thins it out so contaminants drain completely. Park on a flat surface, engage the parking brake, and elevate the front end securely. Open the hood and remove the oil filler cap to vent the crankcase, allowing oil to flow faster.

Step 2: Drain the Old Oil

Locate the oil pan underneath the engine. Unlike many cars where the drain plug faces sideways or backward, Subaru positions the metal drain plug on the bottom of the pan facing downward or slightly angled.

1. Place your drain pan directly beneath the plug.
2. Loosen the 14mm drain plug counterclockwise using your socket wrench.
3. Unscrew it by hand during the final turns, pushing inward slightly to keep oil from leaking past your fingers until it pops free. Let the oil drain completely for 5 to 10 minutes.
4. Wipe the drain pan mating surface clean. Place a new crush washer onto the drain plug and thread it back in by hand to avoid cross-threading. Tighten it snugly with the wrench (torque specification is typically around 30 ft-lbs, or firm hand-tight).

Step 3: Replace the Oil Filter

Subaru places the oil filter right on top of the engine bay near the front for most modern Impreza models, making changes mess-free compared to underside filters.

1. Locate the cylindrical oil filter cartridge near the top front of the engine block.
2. Turn the old filter counterclockwise using an oil filter wrench if it's tight. Place a rag underneath to catch any minor drips.
3. Check the old filter to ensure its rubber O-ring gasket came off with it. Sometimes the rubber gasket sticks to the engine mounting base; leaving it on creates a dangerous double-gasket leak.
4. Dip a clean finger in fresh engine oil and smear a thin film across the rubber gasket of your new filter. This ensures a proper seal and makes future removal easier.
5. Screw the new filter on by hand until it seats firmly, then turn it an extra three-quarters to one full turn. Do not use a wrench to tighten the new filter, as over-tightening ruins the gasket.

Step 4: Refill and Test

1. Insert your funnel into the valve cover oil opening.
2. Pour in 4.5 quarts of your fresh synthetic oil.
3. Remove the funnel, replace the oil filler cap securely, and pull out the dipstick to wipe it clean. Reinsert it fully and pull it out again to check the level. Add oil in small increments until the fluid level sits right at the upper full dot on the dipstick.
4. Start the engine and let it idle for 30 seconds. Verify that the oil pressure dashboard warning light turns off promptly. Look underneath with a flashlight to ensure zero leaks around the drain plug and filter.
5. Turn off the engine, wait two minutes for oil to settle back into the pan, and recheck the dipstick level one final time.

For broader automotive maintenance standards and safety recalls, consult the National Highway Traffic Safety Administration.

How to Reset the Maintenance Reminder Light

Modern Impreza touchscreens and instrument clusters track your oil life digitally.

1. Turn your ignition key to the ON position (or press the push-button start twice without holding the brake).
2. Use the steering wheel directional pad or touchscreen menu to navigate to Settings.
3. Select Maintenance, then choose Engine Oil.
4. Update the mileage interval or date, and select Reset.

If your model uses a physical trip meter knob on the dash, press and hold the trip stem while the ignition is on until the maintenance display resets to zero.

Frequently Asked Questions

Can I mix synthetic and conventional oil in my Impreza?

Mixing them in an emergency won't destroy your engine, but it dilutes the protective benefits of the synthetic oil. If you mix them, plan to complete your next full oil change sooner than usual.

What happens if I overfill my Impreza's oil?

Overfilling causes the crankshaft to whip the oil into a frothy foam. This aerated foam cannot properly lubricate bearings, leading to high internal pressure, blown seals, and potential engine damage. Drain excess oil immediately if the dipstick reads significantly above the full mark.

Why does my Subaru Impreza consume oil between changes?

Flat boxer engines naturally experience minor oil consumption due to cylinder wall design and piston ring movement, especially in higher-mileage units. Checking your oil level every other fuel fill-up prevents running dangerously low between scheduled changes.