2021 Toyota RAV4 Serpentine Belt Routing & Length

Quick answer

For most 2021 Toyota RAV4 models, particularly those with the 2.5L 4-cylinder engine (A25A-FKS):

• Belt Length: Approximately 935mm (36.8 inches)
• Rib Count: 6-rib
• OEM Belt PN: Toyota 90916-A2003
• Aftermarket Cross-references:
  • Gates: K060368
  • Dayco: 5060368
  • Continental Elite: 4060368
• Auto-Tensioner PN: Toyota 16620-0R050 (or 16620-0R051/2/3 depending on specific production run)
• Idler Pulley PN: Toyota 16603-28040 (or 16603-28041/2 depending on specific production run)

Note: Always verify part numbers with your VIN for the most accurate fitment, as minor variations can occur.

Belt Routing

The 2021 Toyota RAV4 with the 2.5L engine utilizes a single serpentine belt to drive accessories like the alternator, air conditioning compressor, power steering pump (electric on some models, so not always a belt-driven pump), and water pump. Before you even think about removing the old belt, STOP AND TAKE A PHOTO! This crucial step will save you immense frustration during reassembly. The path described below assumes you are facing the front of the vehicle.

1. Crankshaft Pulley: Start at the largest pulley at the bottom, which is the crankshaft pulley. This is the main drive pulley.
2. A/C Compressor: From the crankshaft pulley, the belt typically goes up and to the right (passenger side) to wrap around the air conditioning compressor pulley.
3. Idler Pulley: After the A/C compressor, the belt usually routes to an idler pulley, which helps guide the belt and maintain proper tension. This might be located above or to the left of the A/C compressor.
4. Alternator: From the idler pulley, the belt continues upwards to the alternator pulley, often located towards the top of the engine bay on the passenger side.
5. Water Pump: The belt then typically travels across the engine towards the water pump pulley, which is essential for engine cooling.
6. Tensioner Pulley: Finally, the belt will wrap around the tensioner pulley. This pulley is mounted on an automatic tensioner arm, which provides constant tension to the belt. From the tensioner, the belt loops back down to the crankshaft pulley, completing the path.

Remember, your photograph is your best friend for this process!

How to replace the serpentine belt

Replacing the serpentine belt on your 2021 Toyota RAV4 is a manageable DIY task for most home mechanics. You will need a serpentine belt tool or a 3/8-inch breaker bar (or a long ratchet) to release the tension on the automatic tensioner.

1. Safety First: Ensure the engine is off and cool. Disconnect the negative terminal of the battery for added safety.
2. Map it Out: Refer to the photo you took earlier or a routing diagram to understand the belt's path.
3. Locate the Tensioner: Identify the automatic belt tensioner. It will have a square opening (usually 3/8-inch or 1/2-inch drive) designed for a breaker bar or serpentine belt tool.
4. Release Tension: Insert your breaker bar or serpentine belt tool into the square opening on the tensioner. Rotate the tensioner (usually clockwise, but sometimes counter-clockwise – observe which way releases tension) to relieve pressure on the belt. This will allow you to slip the belt off one of the pulleys.
5. Remove Old Belt: Once tension is released, carefully remove the old belt from all the pulleys.
6. Inspect Pulleys: While the belt is off, inspect all the pulleys (alternator, A/C compressor, water pump, idlers) for any signs of wear, wobbling, or noise when spun by hand. Replace any suspect pulleys.
7. Install New Belt: Route the new belt according to your diagram or photo, leaving the tensioner pulley for last. Make sure the ribs on the belt align perfectly with the grooves on all the pulleys.
8. Tension and Release: With the new belt mostly in place, re-apply pressure to the tensioner with your tool, slip the belt over the tensioner pulley, and slowly release the tensioner. Double-check that the belt is seated correctly on all pulleys.
9. Reconnect Battery & Test: Reconnect the battery. Start the engine and let it run for a few minutes, observing the new belt to ensure it tracks correctly and there are no unusual noises.

Replacement interval

Toyota generally recommends inspecting the serpentine belt at every service interval (typically every 5,000 to 10,000 miles) and replacing it as needed. While there isn't a strict mileage-based replacement schedule for the serpentine belt itself, a good rule of thumb is to consider replacement every 60,000 to 100,000 miles, or sooner if signs of wear are present. The automatic tensioner and idler pulleys should also be inspected and replaced if they show any signs of wear or excessive play.

Signs of a failing belt or tensioner

Ignoring a failing serpentine belt or tensioner can lead to significant issues, including loss of power steering, A/C, engine overheating (due to water pump failure), and ultimately a stranded vehicle.

Belt Warning Signs:

• Squealing or Chirping Noises: This is one of the most common indicators, especially on cold starts, during acceleration, or when turning the steering wheel. It often suggests a loose, worn, or misaligned belt.
• Cracks or Fraying: Visually inspect the belt. Deep cracks, missing chunks, fraying edges, or a glazed (shiny) appearance are all signs of a belt that needs immediate replacement.
• Loss of Power to Accessories: If your air conditioning isn't blowing cold, your power steering is stiff, or your battery light is on (indicating the alternator isn't charging), the serpentine belt could be slipping or broken.
• Rubbing or Thumping Noises: If the belt is severely misaligned or damaged, it might rub against other components, causing unusual noise.

Tensioner Warning Signs:

• Belt Squeal (even after belt replacement): If you've replaced the belt and still hear squealing, the tensioner might not be providing adequate tension.
• Wobbling Pulley: Observe the tensioner pulley while the engine is running (from a safe distance). If it's wobbling excessively, the bearing is likely failing.
• Grinding or Growling Noise: A failing tensioner bearing can produce these metallic noises.
• Corrosion or Rust: Visible corrosion on the tensioner assembly can indicate internal issues.
• Lack of Tension: With the engine off, try to twist the belt more than 90 degrees in the longest span. If it twists easily, the tensioner might be weak.

Address these symptoms promptly to avoid broader engine issues and unexpected breakdowns.

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