2017 Subaru Crosstrek Serpentine Belt Routing & Part Numbers

Quick Answer

• Belt Length: 80.5 inches (2045 mm)
• Rib Count: 6-rib
• OEM Belt Part Number: 809221190
• Aftermarket Cross-references:
  • Gates K060805
  • Dayco 5060805
  • Continental Elite 4060805
• Auto-Tensioner Part Number: 13451AA060
• Idler Pulley Part Number: 23770AA020 (Smooth Idler Pulley)

Belt Routing

Before you begin any work, it's highly recommended to take a clear photograph of your existing serpentine belt routing. This will serve as an invaluable reference during reinstallation.

The 2017 Subaru Crosstrek, with its 2.0L naturally aspirated engine, typically routes its serpentine belt in the following common Subaru pattern:

1. Starting from the crankshaft pulley (the lowest and largest pulley, centrally located),
2. The belt travels upward to the A/C compressor pulley (located on the passenger side, lower front of the engine).
3. From the A/C compressor, the belt goes to the smooth idler pulley (a small, smooth pulley typically located above the A/C compressor).
4. Next, the belt wraps around the alternator pulley (located higher up on the passenger side).
5. From the alternator, it makes its way to the power steering pump pulley (typically located on the driver's side, higher up).
6. After the power steering pump, the belt often routes to the water pump pulley (usually on the driver's side, lower than the power steering pump).
7. Finally, the belt goes around the automatic tensioner pulley (located towards the center or passenger side of the engine, designed to maintain proper belt tension) before returning to the crankshaft pulley.

Keep in mind that minor variations can exist, even within the same model year if there are different engine options or accessory configurations. Always double-check your specific vehicle's routing against a diagram or your own photo.

How to Replace the Serpentine Belt

Replacing the serpentine belt on your 2017 Subaru Crosstrek is a job that can be done at home with the right tools and a bit of mechanical know-how.

1. Gather Your Tools: You'll need a serpentine belt tool or a long 3/8-inch drive breaker bar to release the tension on the automatic tensioner.
2. Locate the Automatic Tensioner: This component has a pulley and a square opening (usually 3/8-inch) for your tool.
3. Release Belt Tension: Insert your breaker bar into the square opening of the tensioner. Apply steady pressure clockwise (or counter-clockwise, depending on your vehicle model—observe the direction the tensioner arm moves) to rotate the tensioner arm and release tension on the belt. Do not force it.
4. Remove the Old Belt: While holding the tensioner in the released position, carefully slip the old belt off the pulleys. Start with an easy-to-reach pulley like an idler or the alternator.
5. Inspect Pulleys and Tensioner: Once the belt is off, carefully inspect all pulleys for any play, wobbles, or unusual noises when spun by hand. Check the automatic tensioner for proper function; it should move smoothly and return firmly. Replace any worn components.
6. Route the New Belt: Following your photograph or a diagram, carefully route the new belt around all the pulleys, leaving the tensioner pulley or one other easy-to-reach pulley for last.
7. Final Installation: Apply pressure to the tensioner again with your tool, slip the belt onto the final pulley, and slowly release the tensioner. Ensure the belt is properly seated in all the grooves of every pulley.
8. Double-Check: Visually inspect the entire routing to ensure the belt is correctly aligned and seated on all pulleys.
9. Start the Engine: Briefly start the engine and listen for any squealing or unusual noises. Turn off the engine and re-check the belt alignment.

Replacement Interval

Subaru typically recommends inspecting the serpentine belt at every oil change and replacing it if signs of wear are present. Generally, serpentine belts have a lifespan of around 60,000 to 100,000 miles, or about 4-6 years, whichever comes first. However, driving conditions and climate can affect this. If you frequently drive in dusty environments or extreme temperatures, earlier replacement might be necessary. It's always best to follow your vehicle's maintenance schedule outlined in your owner's manual.

Signs of a Failing Belt or Tensioner

Ignoring a failing serpentine belt or tensioner can lead to serious issues, including loss of power steering, A/C, and charging system failure. Keep an eye out for these warning signs:

• Squealing or Chirping Noises: This is one of the most common indicators of a worn or misaligned belt, or a failing tensioner/pulley. The noise will often be most noticeable during cold starts or when turning the steering wheel (if it's power steering related).
• Cracks, Fraying, or Glazing on the Belt: Visually inspect the belt. Cracks on the ribbed side, frayed edges, or a shiny, glazed appearance are all signs that the rubber is deteriorating and the belt needs replacement.
• Loss of Power Steering, A/C, or Battery Light: If the belt breaks or slips significantly, you will lose the function of the accessories it drives. The battery light may illuminate if the alternator stops charging.
• Wobbling Pulleys: With the engine off, inspect the pulleys for any noticeable wobble or excessive play. A wobbling pulley, especially the tensioner or an idler, indicates a worn bearing.
• Tensioner Not Holding Tension: If the automatic tensioner isn't applying adequate pressure, the belt can slip, leading to noise and reduced accessory performance. You might observe the tensioner arm bouncing excessively during engine operation.

Timely replacement of these components is crucial for the reliable operation of your Crosstrek.

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