2020 Subaru Outback Serpentine Belt Routing & Replacement

Quick Answer

For the 2020 Subaru Outback, the serpentine belt system is relatively straightforward. There are two primary engine options, and it's essential to identify which one your Outback has for accurate part numbers. The most common engine is the 2.5L naturally aspirated (non-turbo) engine, and a 2.4L turbocharged engine is also available on higher trims (Onyx XT, Limited XT, Touring XT).

For 2.5L Naturally Aspirated Engine:

• Belt Length: Approximately 88.5 inches (2248 mm)
• Rib Count: 6-rib
• OEM Belt PN: 840880590 (Subaru)
• Aftermarket Cross-references:
  • Gates K060885
  • Dayco 5060885
  • Continental Elite 4060885
• Auto-Tensioner PN: 23769AA010 (Subaru)
• Idler Pulley PN: 23770AA020 (Subaru)

For 2.4L Turbocharged Engine (XT Models):

• Belt Length: Approximately 90.5 inches (2298 mm)
• Rib Count: 6-rib
• OEM Belt PN: 840881180 (Subaru)
• Aftermarket Cross-references:
  • Gates K060905
  • Dayco 5060905
  • Continental Elite 4060905
• Auto-Tensioner PN: 23769AA010 (Subaru) - Verify this with a parts supplier as it may be the same as the 2.5L or a new PN
• Idler Pulley PN: 23770AA020 (Subaru) - Verify this with a parts supplier as it may be the same as the 2.5L or a new PN

Belt Routing

The serpentine belt on your 2020 Subaru Outback snakes its way around several vital engine accessories. Before you even think about removing the old belt, it is highly recommended to take a clear photograph of the existing belt's routing. This will serve as an invaluable guide when installing the new belt.

Here's a generalized routing path for most 2020 Subaru Outbacks (slight variations might exist based on engine/options, so always refer to your photo):

1. Begin at the Crankshaft Pulley (the large pulley at the bottom, usually ribbed on both sides or with a smooth back from which the belt receives power).
2. From the crankshaft, the belt typically goes up and over the A/C Compressor Pulley (often located on the lower passenger side of the engine bay).
3. After the A/C compressor, it will likely route to an Idler Pulley (a smooth, non-driven pulley used to guide the belt or add tension).
4. From the idler, the belt will stretch up to the Alternator Pulley (usually located high on the driver's side or top of the engine, responsible for charging the battery).
5. Next, it will wrap around the Power Steering Pump Pulley (if equipped with hydraulic power steering; often on the top passenger side, or if electric, this pulley may be absent or a dummy pulley).
6. The belt then typically moves down to the Water Pump Pulley (often centrally located or on one side, crucial for engine cooling).
7. Finally, the belt connects to the Automatic Tensioner Pulley (this pulley applies constant tension to the belt; you'll use this point to relieve tension during removal/installation). The belt will then complete its loop back to the crankshaft pulley.

How to Replace the Serpentine Belt

Replacing the serpentine belt on your 2020 Subaru Outback is a job that most DIYers can tackle with the right tools. Ensure the engine is cool before starting.

Tools You'll Need:

• Serpentine belt tool or a long 3/8-inch drive breaker bar/ratchet
• Socket to fit the tensioner bolt (often 14mm, 17mm, or 19mm)
• New serpentine belt, auto-tensioner (if replacing), and idler pulley (if replacing)

Steps:

1. Locate the Automatic Belt Tensioner: Identify the pulley that is part of the tensioner assembly. It will typically have a square hole (for a 3/8-inch drive tool) or a hexagonal bolt head.
2. Relieve Tension: Insert your serpentine belt tool or breaker bar into the square hole or onto the hexagonal bolt head of the tensioner. Apply steady pressure to rotate the tensioner, which will pivot and reduce tension on the belt. Ensure you rotate it in the correct direction – usually towards the engine block or upwards, relieving tension.
3. Remove the Old Belt: While holding the tensioner in the relieved position, slip the old serpentine belt off one of the pulleys (the easiest is usually the alternator or power steering pump).
4. Inspect Pulleys: With the belt removed, inspect all pulleys (alternator, A/C compressor, water pump, idlers) for any wobble, excessive play, or grinding noises when spun by hand. This is also a good time to replace the auto-tensioner and/or idler pulley if they show signs of wear.
5. Route the New Belt: Following the photograph you took earlier (or the routing description above), carefully route the new serpentine belt around all pulleys, leaving only one pulley (typically the tensioner or an easy-to-reach idler/alternator) as the last point to slip the belt over.
6. Tension the New Belt: Again, apply pressure to the automatic tensioner to relieve tension. Slip the new belt over the final pulley. Slowly release the tensioner, ensuring the belt seats correctly in all the pulley grooves.
7. Double-Check: After releasing the tensioner, visually inspect the entire belt path to ensure it is properly seated in all grooves on all pulleys. Start the engine briefly and listen for any abnormal noises. If there are squeals or chirps, re-check the belt routing and tension.

Replacement Interval

Subaru typically recommends inspecting the serpentine belt at every service interval (usually every 12 months or 12,000 miles, whichever comes first). While belts are designed for longevity, it's generally advised to consider replacing the serpentine belt and possibly the auto-tensioner and idler pulley(s) between 60,000 to 100,000 miles, or every 5-7 years, whichever comes first. However, this can vary significantly based on driving conditions and climate. Always refer to your 2020 Subaru Outback owner's manual for the most accurate maintenance schedule.

Signs of a Failing Belt or Tensioner

Ignoring a failing serpentine belt or tensioner can lead to significant issues, as these components drive crucial accessories. Be aware of the following warning signs:

• Squealing or Chirping Noises: This is the most common sign. A persistent squeal, especially on cold starts, acceleration, or when turning corners, often indicates a worn, glazed, loose, or misaligned belt. It can also point to a failing tensioner or a worn pulley bearing.
• Visible Cracks, Fraying, or Glazing: Inspect the belt visually. Look for small cracks on the ribbed side, fraying along the edges, missing chunks of ribs, or a shiny, glazed appearance. These are all indicators of a worn belt that needs replacement.
• Loss of Power to Accessories: If your power steering suddenly becomes stiff, your A/C stops blowing cold air, or your battery warning light illuminates (indicating the alternator isn't charging), your serpentine belt may have slipped, broken, or a driven accessory has failed.
• Vibrations or Rumbles: A failing tensioner can sometimes produce a rumbling or vibrating noise. If the tensioner's bearing is failing, it can also cause the belt to vibrate excessively.
• Loose or Wobbly Pulley: If any pulley (including the tensioner or idler pulley) appears loose, wobbly, or makes a grinding noise when spun by hand (with the belt removed), it needs to be replaced immediately.
• Belt Slipping Off Pulleys: If the belt frequently slips off a pulley, this indicates either a severely worn belt, a failing tensioner, or a misaligned pulley.

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