2015 Subaru Legacy Timing Belt vs. Chain Guide — Step-by-Step

If you just bought a 2015 Subaru Legacy and started Googling "timing belt replacement," I want to save you time and money right now: the 2015 Legacy with the FB25 2.5L engine does not have a timing belt. It has a timing chain.

This is one of the most common questions in Subaru owner forums, and it generates a lot of confusion because older Subaru engines — like the EJ25 in the classic Outback, Forester, and older Legacy — famously used a timing belt that required replacement every 60,000–105,000 miles. That replacement was a $400–$900 job.

The FB25 changed that. It's a modern, chain-driven engine. The timing chain is designed to last the life of the engine — you don't schedule a replacement on it the way you would with a belt.

Why the Confusion?

The EJ family and FB family both displace around 2.5L, both are Subaru flat-four engines, and both show up in Legacy, Outback, Forester, and Impreza applications across the years. The crossover point is roughly 2010–2012 depending on the model.

The 2015 Legacy specifically uses the FB25B — the second generation of the FB25 — in all non-turbo configurations. If you have the 3.6R Legacy (6-cylinder), that engine is the EZ36D, which also uses a chain.

Bottom line for 2015 Legacy owners: no timing belt to replace, regardless of trim.

The TSB Note: Timing Chain Noise on FB25

There is a known issue on some FB25 engines involving timing chain noise at cold start. Subaru issued TSB 02-134-15R (and related updates) addressing a rattling or slapping noise from the timing chain area during cold starts. The cause is typically a chain tensioner that doesn't maintain adequate pressure after the engine has been sitting, especially in cold weather.

What it sounds like: A brief rattling noise for 1–5 seconds at cold startup, usually from the front of the engine. It typically goes away quickly once oil pressure builds.

What to do:

1. Don't panic — a brief cold-start rattle that disappears immediately is not catastrophic.
2. Check your oil level and condition — low oil or dirty oil makes this worse.
3. Use 0W-20 full synthetic — the thinner cold-flow viscosity reaches the chain tensioner faster on cold starts.
4. Visit a Subaru dealer if the noise is persistent or occurs at warm operating temperature.

Some 2015 Legacy owners have had chain tensioners replaced under warranty or goodwill at Subaru dealers. If yours is past warranty, Subaru's customer assistance line (1-800-782-2783) has occasionally issued goodwill assistance on this issue.

What You Actually Service on the FB25

Since there's no timing belt, here's what deserves your attention:

Engine Oil — Critical

• Spec: 0W-20 full synthetic
• Capacity: 5.1 quarts with filter (FB25B)
• Interval: 6,000 miles or every 6 months
• The FB25 is known for oil consumption — keep it above the low mark.

CVT Fluid (Lineartronic CVT models)

• Fluid: Subaru CVT-II fluid ONLY
• Interval: Despite "lifetime" designation, most mechanics recommend a drain-and-fill every 30,000–60,000 miles
• See the OwnerDrop CVT fluid guides for the procedure

Spark Plugs

• FB25B plugs: NGK SILZKAR7A11 (iridium, OEM spec)
• Torque: 14 ft-lbs (19 Nm)
• Interval: 60,000 miles

Drive Belt (Accessory Belt)

• The FB25 has a serpentine accessory belt — this is NOT the timing chain
• Inspect at every oil change; replace every 60,000–100,000 miles

Comparing: EJ25 vs. FB25

Feature	EJ25 (2009 and older Legacy)	FB25 (2010+ Legacy)
Timing system	Belt	Chain
Replacement interval	60,000–105,000 miles	Not required
Interference engine?	Yes	Yes
Cold start noise concern	Less common	Documented TSB issue

The Takeaway

If you own a 2015 Legacy with the FB25: no timing belt to replace — save that $400–$900. Watch for cold-start chain noise (not catastrophic if brief, but worth monitoring). Change the oil on schedule — 0W-20 full synthetic every 6,000 miles. Don't neglect the CVT fluid.

For all Subaru Legacy maintenance guides including oil changes, spark plugs, and CVT service, see the OwnerDrop blog.

Get the full guide + every torque spec in the OwnerDrop library — OwnerDrop /pricing.