2018 Honda Odyssey Serpentine Belt Routing & Length

Quick Answer

• Engine Application: 3.5L V6 (J35Y6)
• Serpentine Belt Rib Count: 6-Rib
• Serpentine Belt Length: Approximately 85.8 inches (2180mm)
• OEM Belt Part Number: Honda 31110-RLV-A02
• Aftermarket Belt Cross-References: Gates K060858, Dayco 5060860, Continental 4060858
• Automatic Belt Tensioner Assembly: Honda 31170-RLV-A02 (Aftermarket e.g., Gates 39365, Dayco 89728)
• Idler Pulley: The 2018 Odyssey's 3.5L V6 does not use a separate idler pulley in the serpentine belt system; the function is handled by the tensioner pulley.

2018 Honda Odyssey Belt Routing

The 2018 Honda Odyssey is equipped with a single serpentine belt that drives all the engine's accessories. Correct routing is critical for proper function and to prevent damage to the belt or the accessories it drives. For all 2018 models with the 3.5L V6 engine, the belt follows a specific path around seven pulleys.

Before you remove the old belt, we strongly recommend taking a clear photograph of the belt's path or sketching a simple diagram. This small step can save significant time and frustration during reassembly.

The belt routing, starting from the crankshaft and moving clockwise, is as follows:

1. The belt wraps around the main crankshaft pulley at the bottom of the engine.
2. From the crank, it travels up to the A/C compressor pulley.
3. Next, it moves across to the alternator pulley.
4. From the alternator, it goes down to the power steering pump pulley.
5. It then wraps around the water pump pulley.
6. Finally, it travels to the auto-tensioner pulley, which applies pressure to maintain belt tension.
7. The belt then returns to the crankshaft pulley to complete the loop.

How to Replace the Serpentine Belt

Replacing the serpentine belt on the 3.5L V6 engine is a manageable task for an experienced DIYer. The key is releasing the belt tension. The automatic tensioner has a 19mm hex or a 3/8-inch square drive cast into its body.

1. Locate the Tensioner: The tensioner is located between the water pump and the crankshaft pulley.
2. Release Tension: Insert a serpentine belt tool or a long-handled 3/8" breaker bar into the designated slot on the tensioner arm. Rotate the tensioner clockwise (towards the rear of the vehicle) to release the pressure on the belt.
3. Remove the Belt: While holding the tensioner, carefully slip the belt off one of the smooth, accessible pulleys like the water pump or tensioner pulley itself.
4. Install the New Belt: Following your photo or diagram, carefully route the new belt around all the pulleys, saving one of the easiest-to-reach pulleys for last. Double-check that the ribs of the belt are properly seated in the grooves of each pulley.
5. Apply Tension: Slowly release the breaker bar, allowing the tensioner to apply pressure to the new belt. Visually inspect the belt path one last time to ensure it is correctly routed and seated.

Replacement Interval

Honda does not specify a strict mileage replacement interval for the serpentine belt. Instead, it relies on the Maintenance Minder system, which will show a service code (typically including a "2") when inspection is due. As a general rule, it is wise to inspect the belt during every oil change and plan for replacement between 60,000 and 100,000 miles, depending on operating conditions. Belts in hotter climates or those subjected to frequent stop-and-go driving may wear out sooner.

Signs of a Failing Belt or Tensioner

A worn belt or failing tensioner can leave you stranded. Pay attention to these warning signs:

• Squealing or Chirping Noises: This is the most common symptom, often worse on cold starts or during sharp turns. The noise indicates the belt is slipping.
• Visible Wear on Belt: Inspect the belt for cracks, fraying, glazing (shiny surface), or missing ribs. Any visible damage warrants immediate replacement.
• Grinding or Rumbling Noise: A continuous grinding or rumbling noise from the engine bay that changes with engine RPM often points to a failing bearing inside the tensioner pulley.
• Excessive Tensioner Movement: While the engine is running, observe the tensioner arm. A small amount of vibration is normal, but if the arm is bouncing erratically, the internal damping mechanism has likely failed.

If you notice any of these signs, it's best to address the issue promptly. If you're not comfortable performing the replacement yourself, Repairius can help.

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