2021 Subaru Forester Oil Specs

2021 Subaru Forester 2.5 L horizontally opposed 4-cylinder FB25 (152 cu-in / 2,498 cc) Oil Specifications

Viscosity

0W-20

OEM Spec / API

API SN or SN PLUS (Resource Conserving) or ILSAC GF-5

Capacity

4.4 quarts

From Subaru of America, Inc., 2021MY Forester Owner's Manual (MSA5M2102A_STIS_opt). See the cited pages.

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Complete Oil Specifications

Subaru’s owner’s manual for the 2021 Forester (FB25) says to always use SUBARU approved engine oil. If that isn’t available, it lists an alternative: 0W-20 synthetic oil with an API classification of SN or SN PLUS with the words “Resource Conserving”, or ILSAC GF-5 (Starburst mark).

Engine oil capacity is 4.4 US qt (4.2 L) when changing the oil and filter. Subaru calls these quantities a guideline.

Can I Use 5W-30?

Only to top up. If 0W-20 synthetic oil isn’t available, SAE 5W-30 conventional oil may be used when you need to add oil, but Subaru says it should be changed to 0W-20 synthetic at the next oil change.

What We Couldn’t Confirm

Oil change interval. Not stated in the owner’s manual pages used here.
OEM oil filter part number and drain plug torque. Neither appears in the owner’s manual pages used here.

FAQs

What oil does a 2021 Subaru Forester 2.5L 4-Cylinder take? SUBARU approved engine oil. If that isn’t available, Subaru’s alternative is 0W-20 synthetic oil with an API classification of SN or SN PLUS with the words “Resource Conserving”, or ILSAC GF-5 (Starburst mark).

How much oil does it hold? About 4.4 US qt (4.2 L) when changing the oil and filter.

Vehicle	Viscosity	Capacity with filter
2024 2.5L	0W-20	4.4 quarts
2021 2.5L 4-Cylinder (this page)	0W-20	4.4 quarts

Subaru Forester oil type and capacity by year

Same engine in other vehicles

Compare the oil type and capacity listed for every vehicle we've checked with the Subaru FB25 2.5L.

Primary source evidence

Subaru of America, Inc. — 2021MY Forester Owner's Manual (MSA5M2102A_STIS_opt)

US market · Model years 2021 · Published/version not dated on document · Pages/tables: Specifications: Engine table p. 502 (FB25, displacement); Engine oil p. 503 to 504 (approved and alternative engine oil, oil grade, SAE viscosity, engine oil capacity)

View official source · Accessed September 29, 2026

Evidence reviewed September 29, 2026.

Disclaimer: These specifications reflect the official documents and applicability shown above as of their access dates. Confirm the requirement against the manual for your VIN before performing maintenance.

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