2023 Toyota Highlander Serpentine Belt Routing, Length & Part Numbers

As an ASE-certified master technician, I regularly see late-model SUVs like the 2023 Toyota Highlander in the bay for routine maintenance. For the 2023 model year, Toyota made a significant change by dropping the traditional 3.5L V6 in favor of a 2.4L turbocharged 4-cylinder engine (T24A-FTS) for the gas-only models. (Note: The 2.5L Hybrid models utilize electric water pumps, A/C compressors, and power steering, and therefore do not have a traditional serpentine belt.)

If you are servicing the 2.4L turbo engine, having the correct part numbers, belt routing, and torque specifications is critical to getting the job done right the first time. Below is your comprehensive guide to the 2023 Toyota Highlander serpentine belt system.

Quick answer

Here are the essential specifications and part numbers for the 2.4L Turbo engine’s drive belt system:

• Belt Type & Rib Count: 6-rib micro-V belt
• Belt Length: Approximately 48.5 inches (varies slightly by aftermarket manufacturer)
• OEM Toyota Belt Part Number: 90916-02781 (always verify with your VIN)
• Aftermarket Cross-References: Gates K060485, Dayco 5060485, Continental Elite 4060485
• Auto-Tensioner Assembly PN: 16620-F2001
• Idler Pulley PN: 16604-F2001

Note: The 2023 Highlander utilizes Electric Power Steering (EPS), meaning there is no power steering pump pulley on the belt route.

Belt routing

Because modern engine bays are incredibly tight, it is highly recommended that you take a clear photograph of your existing belt routing before you remove it.

For the 2023 Toyota Highlander 2.4L Turbo, the routing path is as follows:

1. Start by looping the ribbed side of the belt around the bottom of the Crankshaft Pulley.
2. Route the belt straight up and over the ribbed A/C Compressor Pulley.
3. Bring the belt across to the ribbed Alternator Pulley.
4. Route the flat back of the belt under the smooth Idler Pulley.
5. Bring the ribbed side over the Water Pump Pulley.
6. Finally, pull the flat back of the belt around the smooth Auto-Tensioner Pulley before connecting back down to the Crankshaft.

How to replace the serpentine belt

Replacing the belt on the 2.4L turbo is a straightforward process, but space can be limited.

1. Locate the tensioner: The auto-tensioner is located on the passenger side of the engine block.
2. Release the tension: Using a specialized serpentine belt tool or a long-handled 14mm / 3/8-inch drive breaker bar, rotate the tensioner pulley bolt counterclockwise (towards the front of the vehicle) to relieve tension on the belt.
3. Remove the old belt: Slip the belt off the easiest to reach pulley (usually the alternator or the idler pulley) while holding the tensioner back. Carefully release the tensioner to its resting position.
4. Inspect the pulleys: Spin the alternator, A/C compressor, water pump, idler, and tensioner pulleys by hand. Listen for grinding noises and feel for any wobble or resistance. If the tensioner or idler feels rough, replace them now.
5. Install the new belt: Route the new belt following the path described in the routing section above. Leave the easiest pulley for last.
6. Apply tension: Rotate the tensioner counterclockwise again, slip the belt onto the final pulley, and slowly release the tensioner. Double-check that the belt ribs are perfectly seated in the grooves of all ribbed pulleys.

Replacement interval

For the 2023 Toyota Highlander, the serpentine belt should be visually inspected every 15,000 miles or 18 months. Under normal driving conditions, expect to replace the drive belt between 60,000 and 90,000 miles. However, severe driving conditions (such as extreme heat, towing, or dusty environments) can shorten the lifespan of the EPDM rubber used in modern belts, making replacement necessary closer to the 50,000-mile mark.

Signs of a failing belt or tensioner

Modern EPDM belts don't crack the way old neoprene belts used to. Instead, they wear down like a tire tread. Look out for these symptoms:

• Squealing or chirping noises: Especially on cold startups or when the A/C engages. This indicates a slipping belt or a weak tensioner spring.
• Whirring or grinding sounds: Typically points to a failing bearing in the idler pulley or the auto-tensioner.
• Visible wear: Check for missing ribs, fraying on the belt edges, or a glazed/shiny appearance on the flat side of the belt.
• Loss of accessories: If the belt snaps, you will immediately lose the alternator (battery light will illuminate) and the A/C. The engine may also overheat rapidly if the water pump is belt-driven.
• Tensioner bounce: With the engine running, observe the tensioner. If the arm is bouncing excessively, the internal dampener has failed and the tensioner must be replaced.

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