2018 Toyota Tundra Serpentine Belt Overview

Quick Answer

• Belt Length: 84.5 inches (approx.)
• Rib Count: 6-rib
• OEM Belt P/N: 90916-A2002
• Aftermarket Cross-references:
  • Gates K060845
  • Dayco 5060845
  • Continental Elite 4060845
• Auto-Tensioner P/N: 16620-0S010
• Idler Pulley P/N: 16603-0S010

Belt Routing (5.7L V8 Engine)

Before you begin any work, take a clear photo of the existing belt routing! This will be your best guide for reinstallation. The serpentine belt on your 2018 Toyota Tundra with the 5.7L V8 engine follows a specific path to drive various accessories. Starting from the crankshaft pulley, the belt typically routes as follows:

1. From the Crankshaft Pulley, the belt travels upward to the right.
2. It then wraps around the A/C Compressor Pulley.
3. From the A/C compressor, the belt continues upwards and loops over the smooth top of the Idler Pulley.
4. The belt then moves down and around the grooved pulley of the Alternator.
5. Next, it travels horizontally to the left, wrapping around the Power Steering Pump Pulley.
6. From the power steering pump, it continues to the Water Pump Pulley.
7. Finally, the belt goes down to the Automatic Tensioner Pulley, which maintains proper belt tension. The belt exits the tensioner and returns to the crankshaft pulley, completing the path.

Note: This routing is typical for the 5.7L V8 engine. Other engine options may have slight variations, but the general principle remains the same. Always refer to a service manual or visual diagram specific to your engine if unsure.

How to Replace the Serpentine Belt

Replacing the serpentine belt on your 2018 Toyota Tundra is a manageable DIY task, but proper tools and caution are essential.

1. Safety First: Ensure the engine is off and cool. Disconnect the negative terminal of the battery to prevent accidental starts.
2. Locate the Tensioner: Identify the automatic belt tensioner. It will have a square opening or a bolt head where you can apply leverage.
3. Release Tension: Use a serpentine belt tool or a 3/8" breaker bar (depending on the tensioner design) inserted into the square hole or onto the bolt head. Rotate the tensioner to relieve tension on the belt. This will typically be counter-clockwise.
4. Remove Old Belt: While holding the tensioner in the loosened position, carefully slip the belt off one of the pulleys (often the idler or alternator is easiest).
5. Inspect Pulleys: With the belt removed, inspect all pulleys for wear, wobbling, or excessive play. Replace any faulty pulleys, including the tensioner and idler, as needed.
6. Route New Belt: Using your photo as a guide, carefully route the new belt around all pulleys, leaving the tensioner pulley or one other easy-to-access pulley for last.
7. Final Installation: Apply the serpentine belt tool/breaker bar to the tensioner again, rotate it to release tension, and slip the new belt onto the remaining pulley. Ensure the belt is seated correctly in all pulley grooves.
8. Verify Routing: Double-check that the belt is correctly routed on all pulleys according to your photo or diagram.
9. Reconnect Battery: Reconnect the negative battery terminal.
10. Test: Start the engine and listen for any abnormal noises. Let it run for a few minutes and then re-inspect the belt for proper alignment and tension.

Replacement Interval

Toyota generally recommends inspecting the serpentine belt at regular service intervals, typically every 15,000 to 30,000 miles, and replacing it if signs of wear are present. Many technicians recommend proactive replacement between 60,000 to 100,000 miles, or if any of the following signs appear sooner.

Signs of a Failing Belt or Tensioner

Ignoring a failing serpentine belt or tensioner can lead to serious issues, as these components are vital for your Tundra's operation. Look out for these warning signs:

• Squealing or Chirping Noises: This is one of the most common indicators. A worn or misaligned belt, or a failing tensioner/pulley bearing, can cause these sounds, especially during cold starts or when turning the steering wheel.
• Cracks, Fraying, or Glazing on the Belt: Visually inspect the belt's ribbed side. Cracks, missing chunks, or a shiny, glazed appearance indicate wear and a loss of grip.
• Loss of Power to Accessories: Since the serpentine belt drives components like the power steering pump, alternator, and A/C compressor, a failing belt can lead to issues such as:
  • No Power Steering: Difficult to turn the steering wheel.
  • Dead Battery/Charging System Light: The alternator isn't charging the battery effectively.
  • No Cold Air from A/C: The A/C compressor isn't engaged.
• Visible Pulley Wobble: If any pulley appears to wobble while the engine is running, particularly the tensioner or idler pulley, it's a sign of a bad bearing and needs immediate attention.
• Belt Slipping Off: A severely worn belt or a failed tensioner can cause the belt to slip off the pulleys entirely, leading to a complete loss of function for all belt-driven accessories.

Catching these signs early and replacing components proactively can save you from a breakdown. If you're unsure about the condition of your belt or tensioner, it's always best to consult with a qualified mechanic.

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