2021 Subaru Outback Serpentine Belt Routing & Replacement Guide

The serpentine belt is a critical component of your 2021 Subaru Outback, powering essential accessories like the alternator, power steering pump, and air conditioning compressor. Regular inspection and timely replacement are crucial for preventing breakdowns and ensuring optimal vehicle performance.

Quick Answer

• Belt Length: Varies by engine (see below)
• Rib Count: 6-rib
• OEM Belt PN: Varies by engine (see below)
• Aftermarket Cross-Reference (Examples): Gates K06xxxx, Dayco 506xxxx, Continental Elite 406xxxx (specific numbers depend on engine and exact length)
• Auto-Tensioner PN: Varies by engine (see below)
• Idler Pulley PN: Varies by engine (see below)

Belt Routing

Important: Before you begin, it’s highly recommended to take a clear photograph of your existing serpentine belt routing. This will serve as a visual guide and prevent errors during reinstallation.

The 2021 Subaru Outback comes with two main engine options: the 2.5L naturally aspirated (FB25DI) and the 2.4L turbocharged (FA24F). While the general principle is the same, the routing might have minor variations.

General Routing (FB25DI 2.5L Naturally Aspirated Engine):

1. Begin at the crankshaft pulley (the large pulley at the bottom, usually ribbed).
2. From the crankshaft pulley, the belt typically goes up to the A/C compressor pulley.
3. From the A/C compressor, the belt may route to an idler pulley (a smooth pulley that guides the belt).
4. Next, the belt wraps around the alternator pulley.
5. From the alternator, it will likely go down to the power steering pump pulley (if applicable, some systems are electric).
6. Then, it will route to the water pump pulley.
7. Finally, it will pass over or under the automatic tensioner pulley before returning to the crankshaft pulley, completing the loop.

General Routing (FA24F 2.4L Turbocharged Engine):

Similar to the 2.5L, but always refer to your under-hood diagram or photograph for the exact path for your specific engine.

How to Replace the Serpentine Belt

Replacing a serpentine belt on your 2021 Subaru Outback is a job that can be done at home with the right tools and a bit of mechanical know-how.

Tools Needed:

• Serpentine belt tool or a 3/8-inch breaker bar/ratchet (for the tensioner)
• Socket set (for removing any covers if necessary)
• Flashlight

Steps:

1. Safety First: Ensure the engine is off and cool. Disconnect the negative battery terminal to prevent accidental starting.
2. Locate the Tensioner: Identify the automatic belt tensioner. It will have a square opening (usually 3/8-inch) for your breaker bar or serpentine belt tool.
3. Relieve Tension: Insert your breaker bar into the tensioner