Genuine Subaru 15255AA170 Oil Filler Cap | Legacy, Outback, Forester, WRX 2003-2021

Genuine Subaru 15255AA170 Engine Oil Filler Cap

Smelling hot oil after a drive, or finding an oily film around the oil filler neck? On higher-mileage Subarus the filler cap's O-ring hardens and cracks, and the cap stops sealing. A leaking filler cap lets crankcase vapors escape into the engine bay and allows unfiltered air to be drawn into the engine — small part, real consequences.

The Subaru 15255AA170 "Cap Complete Oil Filler" is the genuine yellow factory cap with a fresh O-ring seal. It is the current Subaru part number, replacing the earlier 15255AA060 and 15255AA100 caps, and covers most Subaru models from 2003 through 2021.

OEM Part Numbers

• 15255AA170
• 15255-AA170
• Replaces: 15255AA060, 15255AA100

Aftermarket Cross Reference

• MOTORAD MO160 (listed for select 2011–2021 Subaru models — a narrower range than this OE cap)
• STANT 10110 (currently sold as MotoRad 10110)

Common Symptoms of a Worn Filler Cap

• Oil odor in the engine bay or oily film around the filler neck
• Hardened, cracked or torn O-ring seal on the old cap
• Cap feels loose, wobbly, or conversely sticks and binds
• Oil seepage traces on the valve cover around the cap

Product Highlights

• ✔ Genuine Subaru OEM part — the same yellow cap your dealer installs
• ✔ Complete cap with O-ring seal — restores a tight seal at the filler neck
• ✔ Stops oil smell, seepage and crankcase vapor leaks at the cap
• ✔ One cap covers most 2003–2021 Subaru models, 2.0–3.6L, non-turbo and turbo
• ✔ Simple twist-on replacement — no tools required

Condition

New, Genuine Subaru OEM part

Product Type

Engine Oil Filler Cap (Cap Complete Oil Filler)

Function

The oil filler cap seals the oil filler neck on the valve cover. A sound O-ring keeps oil and crankcase vapors in and unfiltered air out. When the seal ages, the engine bay picks up an oil smell and residue builds around the neck — replacing the complete cap restores the factory seal.

Compatible Vehicles

Model	Coverage
Subaru Legacy	within 2003–2021
Subaru Outback	within 2003–2021
Subaru Forester	within 2003–2021
Subaru Impreza (incl. WRX / STI)	within 2003–2021
Subaru WRX / WRX STI	2015–2020
Subaru Baja	within 2003–2021
Subaru Tribeca	within 2003–2021

Overall coverage: Subaru models 2003–2021, 2.0–3.6L engines, non-turbo and turbo.

Important: Please verify fitment with your VIN before ordering.

Package Contents

• 1 × Genuine Subaru 15255AA170 Oil Filler Cap (O-ring seal installed)

Technical Specifications

Brand	Subaru
Manufacturer	Subaru Corporation
Part Number	15255AA170
Alternate Part Number	15255-AA170
Replaces	15255AA060, 15255AA100
Seller SKU	subaru_15255AA170 _2
Product Type	Engine Oil Filler Cap
Color	Yellow
Seal	O-ring (included, installed on cap)
Weight (packaged)	Approx. 0.4 lb
Condition	New

Warranty

Manufacturer warranty may vary by supplier, seller, and region. Please contact us before purchase if warranty confirmation is required.

FAQ

Will this fit my WRX or STI?

Yes — the cap is listed for Impreza WRX/STI models within the 2003–2021 range and for the separate WRX/WRX STI line 2015–2020. Verify with your VIN before ordering.

My old cap is numbered 15255AA060 or 15255AA100 — is this the right part?

Yes. 15255AA170 is the current Subaru part number that replaces both 15255AA060 and 15255AA100.

Does it come with the O-ring seal?

Yes. This is Subaru's "Cap Complete Oil Filler" — the cap comes complete with the O-ring seal installed.

Why should I replace the filler cap at all?

The O-ring hardens with age and heat. A cap that no longer seals causes oil smell in the engine bay, residue around the filler neck, crankcase vapor leaks and lets unfiltered air into the engine.

Are there aftermarket equivalents?

MotoRad MO160 (listed for select 2011–2021 Subarus) and Stant 10110 (now sold as MotoRad 10110) cross to this cap. This listing is the genuine Subaru part.