2015 Subaru Crosstrek Serpentine Belt Routing & Replacement Guide

Quick Answer

• Belt Length: 84.75 inches (approximate, always verify)
• Rib Count: 6-rib
• OEM Belt PN: 809221140 (Subaru)
• Aftermarket Cross-references:
  • Gates K060847
  • Dayco 5060848
  • Continental Elite 4060847
• Auto-Tensioner PN: 23769AA002 (Subaru)
• Idler Pulley PN: 23770AA020 (Subaru)

Belt Routing

The 2015 Subaru Crosstrek uses a single serpentine belt to drive multiple accessories. It's crucial to pay close attention to the routing before removing the old belt. We highly recommend taking a clear photograph of the existing belt routing before you begin any removal process. This will serve as an invaluable reference during installation.

The typical routing for the 2015 Subaru Crosstrek (with the FB20 engine) is as follows, starting from the crankshaft pulley:

1. From the Crankshaft Pulley, the belt travels up to the Air Conditioning (A/C) Compressor Pulley.
2. From the A/C Compressor, the belt goes up and to the right to the Idler Pulley.
3. From the Idler Pulley, the belt moves down and to the left to the Alternator Pulley.
4. From the Alternator, the belt continues down to the Power Steering Pump Pulley (if hydraulically assisted; otherwise, it will bypass this pulley if electrically assisted).
5. From the Power Steering Pump (or Alternator if no hydraulic power steering), the belt goes down to the Water Pump Pulley.
6. Finally, from the Water Pump Pulley, the belt loops around the Automatic Belt Tensioner Pulley to complete the circuit back to the Crankshaft Pulley.

Keep in mind that minor variations can exist, especially with different engine configurations (though the Crosstrek primarily uses the FB20 engine in this year range). Always double-check your specific vehicle.

How to Replace the Serpentine Belt

Replacing the serpentine belt on your 2015 Subaru Crosstrek is a manageable DIY task for most mechanically inclined individuals. Here's a general procedure:

1. Safety First: Ensure the engine is cool and the vehicle is securely parked with the parking brake engaged. Disconnect the negative battery terminal to prevent accidental starting.
2. Locate the Tensioner: Identify the automatic belt tensioner. It will have a square drive hole (typically 3/8-inch) for a breaker bar or a serpentine belt tool.
3. Relieve Tension: Insert a 3/8-inch breaker bar or a serpentine belt tool into the square drive hole on the tensioner. Gently rotate the tensioner to relieve tension on the belt. This will allow you to slip the belt off one of the pulleys.
4. Remove Old Belt: Once the tension is relieved, carefully slide the old belt off one of the pulleys (often the idler or a smooth pulley). Then, completely remove the belt from all the pulleys.
5. Inspect Pulleys: While the belt is off, inspect all pulleys for any signs of wear, wobbling, or excessive noise when spun by hand. Replace any worn or noisy pulleys (especially the idler pulley and tensioner assembly).
6. Install New Belt: Route the new belt according to the diagram you photographed or the description above. Start by placing the belt on all the smooth pulleys first, leaving one grooved pulley (like the alternator or A/C compressor) for last, or the tensioner pulley. This makes it easier to work.
7. Apply Tension: Once the belt is mostly routed, use your breaker bar or serpentine belt tool to once again relieve tension on the tensioner. Carefully slip the belt over the remaining pulley. Slowly release the tensioner, ensuring the belt is properly seated in all the grooves of all the pulleys.
8. Double-Check: Before starting the engine, visually inspect the entire belt routing to ensure it's correctly seated on all pulleys and that no part of the belt is twisted or misaligned.
9. Reconnect Battery: Reconnect the negative battery terminal. Start the engine and listen for any unusual noises. Observe the belt for proper operation.

Replacement Interval

Subaru typically recommends inspecting the serpentine belt at every scheduled service interval (e.g., every 15,000 miles or 12 months) and replacing it if signs of wear are present. Generally, a serpentine belt can last anywhere from 60,000 to 100,000 miles, but this can vary significantly based on driving conditions and maintenance. It's always better to replace it proactively if you notice any of the signs of a failing belt.

Signs of a Failing Belt or Tensioner

Ignoring a failing serpentine belt or tensioner can lead to significant problems, including loss of power steering, A/C, and charging system operation, potentially leaving you stranded.

Signs of a Failing Serpentine Belt:

• Squealing or Chirping Noises: This is one of the most common indicators. It can be caused by a loose belt, a worn belt, or misaligned pulleys.
• Cracks or Fraying: Visible cracks on the ribbed side of the belt, missing chunks, or fraying along the edges are clear signs it needs replacement.
• Glazed or Shiny Appearance: If the ribbed side of the belt looks shiny or glazed, it indicates reduced friction and potential slipping.
• Loss of Ribs: Any missing ribs on the belt means it has completely failed and needs immediate replacement.
• Steering Difficulty: If the power steering pump is belt-driven and the belt slips or breaks, you will experience sudden difficulty steering.
• Overheating Engine: A broken belt will stop the water pump from circulating coolant, leading to engine overheating.
• Battery Warning Light: If the alternator ceases to charge the battery due to a broken belt, the battery warning light will illuminate on your dashboard.

Signs of a Failing Belt Tensioner:

• Excessive Belt Squeal (even after belt replacement): A weak tensioner might not be providing adequate tension, causing the belt to slip.
• Belt Slipping or Wobbling: The tensioner's job is to keep constant tension. If it