Note: This article contains affiliate links. If you click on these links and make a purchase, I may earn a small commission at no extra cost to you. This helps support my research and content. Read my full affiliate disclaimer here.
Picking the right oil for a Subaru Impreza matters because the wrong viscosity or formulation can affect fuel economy, wear rates, and engine responsiveness. You want an oil that balances protection, compatibility with Subaru engine requirements, and performance under your usual driving conditions. This guide presents seven shortlisted options that represent the top choices in this category. We evaluated each on real-world durability and suitability for the Impreza, and the following sections explain the criteria used and what to consider before you pick one.
Looking for other parts? See all Subaru Impreza parts & accessories.
Top Picks at a Glance
| Best Reviewed A top-rated pick with lots of positive feedback | Subaru Engine Oil Filter with Crush Washer (15208AA21A) — 2 Pack |  |
| Most Popular A crowd favorite that many people choose with confidence | Newparts Spin-On Engine Oil Filter (Set of 2) for Subaru |  |
| Best Quality Built to a higher standard if you want something more solid | Subaru Genuine Oil Pump Assembly 15010AA360 |  |
| Best Budget The cheapest option that still gets the job done reliably | kweiny Aluminum Engine Oil Filler Cap with O-ring (M42x4.5) for Subaru |  |
| Most Sold A high-volume bestseller chosen again and again | CNS High Performance Engine Oil Pump (12mm Rotor) for Subaru Impreza EJ Engines |  |
| Best Value for Money The sweet spot between price and what you get | Subaru Genuine Engine Oil Filter with Crush Gasket (15208AA21A, 3 Pack) |  |
| Best Overall The best all-around choice for most situations | Motul 8100 X-clean EFE 5W-30 Full Synthetic Motor Oil (5 L) |  |
1. Subaru Engine Oil Filter with Crush Washer (15208AA21A) — 2 Pack
| Thread Size | M16 x 1.5 |
|---|---|
| OEM Part Number | 15208AA21A |
| Vehicle Service Type | Car,Sports Utility Vehicle |
| Number of Items | 1 |
This is the factory Subaru engine oil filter supplied with the correct crush washer for the drain plug, sold as a kit suitable for regular oil changes on compatible Impreza engines. It installs like a standard spin-on filter and is intended for routine maintenance to trap microscopic contaminants and protect the engine between service intervals. Notable features include the updated Subaru part number (15208AA21A) and a fitment list covering non-turbo Impreza years; the package is a direct replacement so no modification is required. Practical benefits are straightforward: correct fit, known filtration performance consistent with Subaru specifications, and the included crush washer removes the need to hunt for separate gaskets. Limitations are minimal for routine users but include the single-purpose nature of the part compared with higher-capacity performance or extended-life aftermarket filters, and you must follow Subaru's recommended oil change schedule for best results.
Best for: Risk-averse mainstream buyers who prioritize factory-spec reliability and want a simple, worry-free replacement that matches Subaru's service recommendations for the Impreza.
Less Ideal for: Enthusiasts seeking higher-flow or extended-interval filters for motorsport or modified engines should consider performance aftermarket options instead.
- Factory replacement filter specified by Subaru for correct fit and filtration.
- Includes crush washer for the oil drain plug for a complete oil change kit.
- Updated part number ensures current manufacturing and compatibility notes.
- Vehicle-specific fit minimizes installation issues and leaks when installed properly.
- Not designed as a performance or extended-life aftermarket filter.
- Sold in basic packaging which may differ from retail boxed presentation.
Verdict If you want a worry-free, factory-specified oil filter and crush washer for your Subaru Impreza, this genuine Subaru kit delivers correct fit and dependable protection.
2. Newparts Spin-On Engine Oil Filter (Set of 2) for Subaru
| Thread Size | 20×1.5 MM |
|---|---|
| Flow Rate | 8-10 GPM |
| Anti-Drain Back Valve | Yes |
| Bypass Relief Valve Setting | 27 |
| Media Material | Synthetic |
This spin-on oil filter is a straightforward replacement designed for Subaru engines and sold as a set of two. It uses synthetic filter media, includes an anti-drain back valve and a bypass relief valve set around 27 psi, and is intended for routine oil changes. Installation is typical for spin-on filters: remove the old unit, hand-thread the new filter and tighten to spec. The synthetic media promises better particle retention versus basic paper elements, which is helpful when running full synthetic engine oils recommended for Subaru boxer engines. Practical benefits are easy fitment to vehicle-specific threads, predictable flow rate, and protection against dry starts thanks to the anti-drain back valve. Limitations are typical of budget replacement filters: construction reports in some reviews vary, and occasional packaging or material complaints suggest quality control is not perfectly consistent. If you expect premium lab-tested performance or extended-service intervals beyond manufacturer recommendations, a top-tier branded performance filter may be a better match.
Best for: Buyers who prioritize convenience and straightforward maintenance routines and want a ready-fit replacement that works with common full synthetic oils.
Less Ideal for: Drivers seeking a lab-verified high-performance or extended-interval filter for motorsport or unusually long oil-change intervals should consider premium branded alternatives.
- Synthetic filter media for improved particle capture compared with basic paper elements
- Built-in anti-drain back valve to reduce dry-start wear
- Vehicle-specific thread size and fitment for straightforward installation on Subaru engines
- Includes bypass relief valve to maintain oil flow under clogged conditions
- Some customer reports cite inconsistent build quality and packaging issues
- Not marketed or tested as a premium extended-life performance filter
Verdict A practical, vehicle-specific replacement oil filter that offers synthetic media and anti-drain protection for convenient Subaru maintenance, though it is not a premium extended-life option.
3. Subaru Genuine Oil Pump Assembly 15010AA360
| Model | 15010AA360 |
|---|---|
| Manufacturer | Subaru |
| Fitment note | Turbocharged Impreza WRX/STI and select Legacy/Outback 2.5L H4 turbo engines |
This genuine Subaru oil pump replaces the factory unit in turbocharged Impreza WRX and STI applications and is used when rebuilding or repairing EJ20/EJ25 turbo engines. Typical use is direct installation during an engine overhaul or as a higher-flow upgrade to improve oil delivery for high-stress turbo duty. Because it is a factory part, fitment and mounting match the original, which simplifies installation and avoids modification. Reviews and product notes indicate this is the commonly referenced 11mm STI-style pump that increases flow compared with the original 10mm unit, helping reduce bearing wear under sustained high RPM or boosted operation. Limitations to consider are occasional reports of relief-valve issues on a small number of units and that this is a direct replacement rather than a performance-designed aftermarket pump with billet internals or increased pressure control features. Expect reliable OEM compatibility but evaluate your engine build goals if you need extreme performance lubrication beyond factory-upgrade flow.
Best for: Practical optimizers looking for a dependable, factory-compatible oil pump that upgrades oil flow without complicating installation or requiring custom work.
Less Ideal for: If you are building a high-horsepower or race-focused Impreza that needs custom pressure control or race-grade internals, consider a dedicated performance pump instead.
- Factory Subaru part so mounting and clearances match the original application for Impreza WRX/STI engines
- Higher-flow 11mm design compared with earlier 10mm pumps to improve oiling on turbocharged EJ engines
- Direct-fit replacement suitable for engine rebuilds and routine service without machining or modification
- Not a bespoke performance pump—lacks advanced aftermarket features like billet gears or modified pressure regulation
- A small number of user reports describe relief-valve sticking which can cause loss of oil pressure in rare cases
Verdict A cost-effective factory replacement that reliably increases oil flow for turbo Impreza engines while keeping installation simple.
4. kweiny Aluminum Engine Oil Filler Cap with O-ring (M42x4.5) for Subaru
| Material | Aluminum alloy |
|---|---|
| Thread specification | M42x4.5 |
| Includes | Cap with seal O-ring |
| Compatibility note | Interchange with 15255AA170, 15255AA100 |
This aluminum oil filler cap replaces the stock plastic cap on compatible Subaru engines and installs in place of the factory part number 15255AA170/15255AA100. It is a one-piece anodized aluminum cap with an O-ring seal and M42x4.5 thread specification, so it works as a direct screw-in replacement for the listed Subaru models. In everyday use it gives a firmer, more durable feel than the original plastic cap and resists cracking from heat and age. The anodized finish improves under-hood appearance and the included seal helps maintain a tight fit to keep oil vapors contained. Limitations are small: alignment of text or aesthetic markings may not orient perfectly when tightened, and buyers must confirm their Impreza engine uses the compatible thread and part number before fitting. Expect a simple hand-tight install with no special tools required and a longer-lasting cap compared with the factory plastic piece.
Best for: Budget-conscious Subaru owners who prioritize a durable, low-cost replacement for a brittle factory plastic oil cap and want a simple upgrade that reduces the chance of cap failure.
Less Ideal for: Those seeking an exact factory cosmetic match or people who need a cap with a different thread or non-listed fitment should look elsewhere.
- Durable one-piece aluminum construction resists cracking and heat over time.
- Anodized finish improves under-hood appearance compared with plastic caps.
- Includes O-ring for a sealed fit to reduce oil vapor leaks.
- Direct-fit M42x4.5 thread and listed interchange with factory part numbers for easy replacement.
- Markings or text can end up misaligned when the cap is tightened, affecting appearance.
Verdict A inexpensive, durable aluminum replacement that prevents the common failure of plastic oil caps on compatible Subaru Impreza engines.
5. CNS High Performance Engine Oil Pump (12mm Rotor) for Subaru Impreza EJ Engines
| Compatible engines | Subaru EJ20 EJ25 and related EJ-series variants |
|---|---|
| Rotor length | 12mm |
| Package contents | Pump, seal, 7 mounting bolts, O-ring |
| Manufacturer | CNS Engine Parts |
This CNS oil pump is an aftermarket replacement built to fit Subaru Impreza models that use EJ-series engines. It replaces the factory pump and is commonly used when rebuilding or upgrading an engine; the 12mm rotor is intended to increase oil flow and oil pressure compared with smaller rotors. The kit ships with the pump seal, mounting bolts, and an O-ring so you have the basic hardware needed for installation. In practice this pump suits a budget rebuild or a performance-focused refresh where higher oil delivery is desired, but installation needs care because alignment of the crank and seal is critical to avoid damaging the seal. Customer reports are mixed: many owners saw good oil pressure and long life when installed correctly and primed, while a few reported early failures that caused serious engine damage. Expect cost savings over factory replacements but accept some risk compared with a factory-quality pump; careful installation, priming, and post-installation oil-pressure checks are essential.
Best for: Budget-conscious Impreza owners who want a lower-cost replacement or a higher-flow pump for a rebuild and are comfortable performing careful installation and oil-pressure verification.
Less Ideal for: Owners seeking an OEM-level pump with minimal risk for a high-value or freshly rebuilt engine should consider a factory-quality replacement instead.
- 12mm rotor increases oil flow and can raise oil pressure for rebuilt or high-stress EJ engines
- Includes pump seal, mounting bolts, and O-ring so you receive basic installation hardware
- Multiple buyers report proper fitment on a range of Impreza EJ engines when installed correctly
- Some users reported premature failures leading to loss of oil pressure and potential engine damage
- Aftermarket quality is variable compared with factory-quality pumps and may lack the same warranty protection
Verdict A cost-effective high-flow replacement for Impreza EJ engines that can boost oil delivery if installed and checked carefully, but it carries higher risk than a factory-quality pump.
6. Subaru Genuine Engine Oil Filter with Crush Gasket (15208AA21A, 3 Pack)
| Thread Size | M16 x 1.5 |
|---|---|
| Material | Synthetic/Cellulose Fibers (Media), Steel/Plastic (Housing) |
| Manufacturer Part Number | 15208AA21A-803916010 |
| Automotive Fit Type | Vehicle Specific Fit |
This genuine Subaru oil filter and crush gasket kit is the factory replacement designed to trap microscopic contaminants and protect the engine during routine oil changes on compatible Impreza models. It installs in the same way as the factory unit and is intended for regular service intervals recommended by Subaru. The filter media is a synthetic/cellulose blend inside a steel/plastic housing and the listing notes the current part supersedes several older part numbers, which helps avoid fitment confusion. Practical benefits are straightforward: a direct-fit, factory-quality filter with the correct thread size and the included crush washer for the drain plug so you have both parts needed for a tidy oil change. Limitations are minor: you get one filter per pack in this listing and packaging may be plain rather than retail-branded, so expect a no-frills presentation. If you want aftermarket performance filters with extended capacity or special anti-drain features, those are not what this factory part provides.
Best for: A practical optimizer looking for a budget-smart, factory-quality replacement that simplifies maintenance and avoids fitment guesswork for the Subaru Impreza.
Less Ideal for: Enthusiasts seeking extended-life or high-flow aftermarket oil filters for modified engines should consider performance-oriented alternatives.
- Factory-designed fit for Subaru engines, ensuring correct alignment and thread engagement.
- Includes the crush gasket so the oil drain is resealed during service.
- Filter media formulated to capture microscopic contaminants for routine protection.
- Updated part number that supersedes older Subaru filters to reduce fitment uncertainty.
- Sold as single filter kits in this listing rather than multi-filter bulk packs.
- No aftermarket performance features such as extended life media or anti-drain back valve enhancements.
- Packaging may be plain white box rather than retail-branded presentation.
Verdict If you want a straightforward, factory-quality replacement for routine oil changes on an Impreza, this Subaru filter with crush gasket delivers dependable value.
7. Motul 8100 X-clean EFE 5W-30 Full Synthetic Motor Oil (5 L)
| Viscosity | 5W-30 |
|---|---|
| Size | 5 l |
| API | SN |
| ACEA | C2/C3 |
Motul 8100 X-clean EFE is a full synthetic 5W-30 engine oil designed to reduce internal friction and support emissions equipment in modern engines. In practical use it is poured during routine oil changes and is intended for vehicles that need ACEA C2/C3 and API SN level oils; the formula uses low-SAPS chemistry and friction modifiers to help preserve particulate filters and catalytic after-treatment while promoting smoother idle and crisper throttle response. Notable features include OEM approvals for several manufacturers and a blend engineered for long-drain intervals and high-temperature stability, which makes it suitable for daily driving, highway cruising, and forced-induction duty where oxidation resistance matters. Limitations to consider are fitment: you must confirm Subaru Impreza engine requirements and manufacturer recommendations before switching, since not all Subaru model years specify 5W-30 or the same ACEA/API ratings, and longer drain intervals should follow the vehicle maker's service schedule. The product is practical for drivers seeking a balance of fuel economy, emissions protection, and engine longevity when matched to the correct Subaru Impreza specification.
Best for: Balanced buyers who prioritize a blend of fuel economy, emissions-system protection, and everyday durability for their Subaru Impreza while following manufacturer service guidance.
Less Ideal for: Drivers who need a different viscosity or a specification not listed by this oil for their Impreza, or those who prefer strictly manufacturer-branded fluids supplied by a dealer.
- 100% synthetic 5W-30 formulation optimized to reduce friction and improve fuel economy.
- Low-SAPS chemistry compatible with particulate filters and emissions systems when the vehicle requires ACEA C2/C3 specs.
- Approved to multiple OEM specifications, indicating broad manufacturer compatibility where those specs are called for.
- Formulated for high-temperature stability and long-drain capability, reducing oxidation and viscosity loss under stress.
- May not match every Subaru Impreza model year or engine specification, so fitment must be verified before use.
- Longer drain claims require adherence to Subaru service intervals and may not apply if the manufacturer recommends shorter changes.
Verdict A versatile, fuel-economy focused full synthetic 5W-30 that works well for Subaru Impreza owners when it matches the vehicle's specified oil requirements.
Choosing the Right Subaru Impreza Engine Oil: Key Factors to Consider
Viscosity and Cold-Start Performance
Viscosity determines how easily oil circulates at different temperatures, which directly affects startup wear and engine protection. For Subaru Impreza engines, choosing the right viscosity helps ensure quick oil flow on cold mornings without sacrificing film strength at operating temperature. Lower numbers before the W improve cold-start flow, while the second number indicates high-temperature protection. Consider your local climate and start-up conditions when selecting viscosity so the oil reduces friction during the most vulnerable moments.
Base Oil Type and Additive Package
The base oil—conventional, synthetic blend, or full synthetic—affects stability, oxidation resistance, and how long the oil can safely go between changes. Full synthetic oils typically offer better thermal stability and consistency of flow, which helps protect modern Subaru engines under stress. Equally important is the additive package. Detergents, dispersants, antiwear agents, and friction modifiers all play roles in cleaning deposits, protecting cam lobes and bearings, and preserving fuel economy. Look for formulations with balanced additive chemistry suited to gasoline engines.
Compatibility With Engine Seals and Materials
Engine oils interact with gaskets, seals, and other materials inside the engine. Some formulations can cause swelling or shrinkage of seals over time, leading to leaks or increased oil consumption. Choosing oils formulated for modern engine materials helps maintain long-term sealing integrity. Manufacturers often test compatibility with common elastomers and coatings. Prioritizing oils that note compatibility with passenger car engine materials reduces the risk of seal-related issues.
Deposit Control and Cleaning Ability
Deposit control matters because sludge and varnish can impair oil flow passages, restrict valvetrain movement, and reduce heat transfer. Oils with effective detergents and dispersants help keep combustion byproducts and degraded oil particles suspended until they are removed at the next oil change. Regularly using an oil with proven cleaning ability can preserve engine efficiency and reduce the chance of performance-robbing deposits accumulating over time.
High-Mileage Considerations
Engines with higher mileage often have increased internal clearances and may consume more oil. High-mileage formulations typically include seal conditioners and higher levels of antiwear additives to address these issues. They may also have additives intended to reduce leaks and slow oil degradation. If your Impreza has substantial mileage, consider oils labeled for high-mileage use or those with additives aimed at replenishing seal pliability and compensating for wear.
Manufacturer Specifications and Warranty Guidance
Following Subaru's published viscosity and specification guidelines helps ensure proper engine protection and avoids potential warranty issues. OEM specs indicate acceptable viscosity ranges and performance standards relevant to the engine design and tolerances. Verify that any oil you consider meets the vehicle manufacturer’s recommended classifications. Staying within specified viscosity and spec guidelines simplifies maintenance decisions and aligns with the engine’s designed operating characteristics.
FAQ
How often should I change the oil in my Subaru Impreza?
Oil-change intervals often depend on driving habits, oil type, and vehicle age. Many drivers follow manufacturer schedules or use condition-based alerts if available. Using a higher-stability oil and monitoring oil condition can safely extend intervals within recommended service limits.
Can I switch between different viscosities in my Impreza?
Switching viscosities occasionally is possible but should remain within the manufacturer’s recommended range. Consistently using a viscosity not suited to your climate or engine condition can affect protection and fuel economy. When in doubt, follow OEM guidance for the best balance.
Is synthetic oil necessary for a Subaru Impreza?
Synthetic oils generally offer better thermal stability and flow at low temperatures, which can enhance protection and longevity. Whether it is necessary depends on driving conditions and engine age, but many owners prefer synthetics for their improved performance characteristics.
What oil viscosity is best for cold climates?
In colder climates, oils with a lower cold-start rating provide faster circulation on startup. Choosing an oil with a lower first number before the W improves flow at low temperatures while still maintaining adequate high-temperature protection. Always confirm the selection aligns with Subaru guidance.
Should I use a high-mileage formulation in an older Impreza?
High-mileage formulations can help address increased oil consumption and aging seals by including conditioners and targeted additives. They are usually beneficial for older engines that show signs of wear, but assess the engine’s condition and maintenance history before deciding.
How We Chose the Best Subaru Impreza Engine Oil
We selected products by focusing on attributes that matter specifically to Subaru Impreza engines. Key evaluation criteria included viscosity match and cold-start performance, base oil type and additive package, long-term thermal stability and oxidation resistance, suitability for high-mileage engines and deposit control, and compatibility with OEM seals and turbocharger requirements where applicable. We also considered manufacturer guidance and reported field reliability for sustained protection under mixed driving. Excluded items included oils matched only to unrelated vehicle families, blends lacking adequate modern additive technology, and formulations that did not meet typical Subaru specifications. The final list emphasizes oils that combine the right viscosity behavior, proven protection against wear and deposits, and good performance in both short trips and sustained highway use.
Our full evaluation process is outlined in our review methodology.
Conclusion
Selecting the right oil for a Subaru Impreza is about matching viscosity to climate and driving style, choosing a base oil and additive package that preserves cleanliness and wear protection, and following manufacturer specifications. Prioritize oils that offer good cold-start flow, deposit control, and compatibility with engine materials. Weigh the tradeoffs between longer drain intervals and the need for seal or deposit control in older engines. Focusing on those core factors will help you maintain performance and extend engine life.
Explore More:
- Check out all Subaru Impreza parts & accessories
- Explore Fluids & Chemicals
- Browse all Accessories
