2018 Toyota Tacoma Serpentine Belt: Routing, Replacement, and Part Numbers

Quick Answer

• Belt Length: Approximately 98.7 inches (2507 mm)
• Rib Count: 6-rib
• OEM Belt Part Number: 90916-A2024 (for 3.5L V6 engine)
• Aftermarket Cross-references:
  • Gates K060987
  • Dayco 5060987
  • Continental Elite 4060987
• Auto-Tensioner Part Number: 16620-0P030 (for 3.5L V6 engine)
• Idler Pulley Part Number: 16603-0P030 (for 3.5L V6 engine)

Belt Routing

The 2018 Toyota Tacoma with the 3.5L V6 engine utilizes a specific serpentine belt routing path. Before you begin any work, it is highly recommended to take a clear photograph of your existing belt routing. This will serve as an invaluable reference during reinstallation.

Starting from the crankshaft pulley (the lowest, central pulley), the belt typically routes as follows:

1. From the crankshaft pulley, the belt goes up and to the left, wrapping around the A/C compressor pulley.
2. From the A/C compressor pulley, the belt then moves upwards to wrap around the smooth idler pulley.
3. Leaving the idler pulley, the belt continues upwards and slightly to the right, engaging the alternator pulley.
4. From the alternator pulley, the belt travels downwards and to the left, around the power steering pump pulley.
5. After the power steering pump pulley, the belt moves across, engaging the water pump pulley.
6. Finally, from the water pump pulley, the belt makes its way to the automatic tensioner pulley, which then completes the loop back to the crankshaft pulley.

Keep in mind that the 2.7L 4-cylinder engine will have a different routing due to its different accessory layout. Always refer to your owner's manual or a service manual specific to your engine for precise routing diagrams.

How to Replace the Serpentine Belt

Replacing the serpentine belt on your 2018 Toyota Tacoma is a task that can be done at home with the right tools and a bit of mechanical know-how. The primary tool you'll need is a serpentine belt tool or a 3/8-inch breaker bar, which will be used to relieve tension on the automatic tensioner.

1. Safety First: Ensure the engine is cool and the vehicle is turned off. Disconnect the negative terminal of the battery for added safety.
2. Locate the Automatic Tensioner: This pulley will have a square hole designed to accept a 3/8-inch drive wrench or a specialized serpentine belt tool.
3. Relieve Belt Tension: Insert your tool into the square hole on the tensioner and rotate it clockwise (or counter-clockwise, depending on the tensioner design) to release the tension on the belt. While holding the tensioner in this position, carefully slide the old belt off one of the pulleys (often the idler or a smooth pulley is easiest).
4. Remove the Old Belt: Once loose, carefully remove the entire old belt from all the pulleys.
5. Inspect Pulleys: Take this opportunity to inspect all the pulleys for any signs of wear, wobbling, or unusual noise. Replace any faulty pulleys (like the idler pulley) or the tensioner if necessary.
6. Install the New Belt: Referring to your photograph or the routing description above, begin routing the new belt, leaving one pulley (again, often an idler or smooth pulley) for last. This last pulley will be where you stretch the belt over for final installation.
7. Apply Tension: Once the belt is mostly in place, use your serpentine belt tool or breaker bar to again rotate the tensioner and create slack. Carefully slip the belt over the last pulley. Ensure the belt is properly seated in all the grooves of every pulley.
8. Verify Routing: Double-check that the belt is correctly routed on all pulleys and that it is not twisted or misaligned.
9. Reconnect Battery and Test: Reconnect the negative battery terminal. Start the engine and let it run for a few moments, observing the belt to ensure it tracks smoothly without any wobbling or chirping. Listen for any unusual noises.

Replacement Interval

Toyota generally recommends inspecting the serpentine belt on your 2018 Tacoma every 15,000 miles or 12 months, and replacing it if signs of wear are present. Many technicians and manufacturers suggest a replacement interval of approximately 60,000 to 100,000 miles for serpentine belts under normal driving conditions. However, this can vary significantly based on driving habits, environmental factors, and engine conditions. Regular inspections are key to determining the actual need for replacement.

Signs of a Failing Belt or Tensioner

Ignoring the warning signs of a failing serpentine belt or tensioner can lead to a breakdown, as the belt drives crucial accessory components like the alternator, power steering pump, water pump, and A/C compressor.

Signs of a failing serpentine belt include:

• Squealing or Chirping Noises: This is one of the most common signs, especially on cold starts or during acceleration. It indicates the belt may be slipping or worn.
• Cracks or Fraying: Visually inspect the belt for cracks, splits, missing ribs, or fraying along the edges. These are clear indicators that the belt needs to be replaced.
• Glazing: A shiny, hardened appearance on the ribbed side of the belt can indicate slippage and reduced friction.
• Loose or Stretched Belt: If the belt feels loose, it might be stretched out, or the tensioner itself might be failing.

Signs of a failing automatic tensioner include:

• Excessive Vibration or Wobbling: If the tensioner pulley is vibrating or wobbling significantly while the engine is running, its internal components may be worn.
• Loss of Tension: If the belt feels abnormally loose, even after being replaced, the tensioner may not be applying adequate pressure.
• Grinding or Growling Noises: Worn bearings within the tensioner pulley can produce these types of mechanical noises.
• Failure to Keep Belt Properly Aligned: A failing tensioner can cause the belt to run off-center on pulleys.

If you notice any of these symptoms, it's crucial to address them promptly to avoid potential damage to your engine or a breakdown.

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