2018 Honda Pilot Serpentine Belt Routing & Replacement Guide

Quick Answer

• Belt Length: 2100mm (82.68 inches)
• Rib Count: 7-rib
• OEM Belt PN: 31110-5J6-A01 (verify with VIN for specific engine)
• Aftermarket Cross-References:
  • Gates: K070827
  • Dayco: 5070825
  • Continental Elite: 4070825
• Auto-Tensioner PN: 31170-5J6-A01 (verify with VIN for specific engine)
• Idler Pulley PN: 31180-5J6-A01 (verify with VIN for specific engine)

Belt Routing

The most crucial step before attempting to remove your serpentine belt is to take a clear photograph of the current belt routing. This will serve as an invaluable reference during reinstallation.

The 2018 Honda Pilot (with the 3.5L V6 engine) typically routes its 7-rib serpentine belt as follows:

1. Crankshaft Pulley: The journey begins at the bottom center of the engine, around the largest pulley, which is the crankshaft pulley. This pulley drives all the other accessories.
2. A/C Compressor: From the crankshaft pulley, the belt goes upwards and to the right (when looking at the front of the engine) to wrap around the air conditioning (A/C) compressor pulley.
3. Idler Pulley: After the A/C compressor, the belt continues upwards and slightly to the left, passing over the smooth idler pulley. This pulley helps guide the belt and maintain proper tension.
4. Alternator: The belt then travels from the idler pulley, making a downward path to the alternator pulley, which is usually located higher up on the passenger side of the engine. The alternator generates electrical power for the vehicle.
5. Power Steering Pump: Following the alternator, the belt moves across horizontally to the power steering pump pulley, typically situated on the driver's side, slightly lower than the alternator. Note: Some Pilot models may have electric power steering, in which case this pulley will not be present.
6. Water Pump: Next, the belt typically goes from the power steering pump to the water pump pulley, which is often located near the center or passenger side of the engine, helping to circulate coolant.
7. Auto-Tensioner: Finally, the belt courses to the automatic tensioner pulley, which is a spring-loaded pulley system that maintains consistent tension on the belt, completing the loop and returning to the crankshaft pulley.

How to Replace the Serpentine Belt

Replacing the serpentine belt on your 2018 Honda Pilot is a manageable DIY task for those with some mechanical experience. You will typically need a serpentine belt tool or a 3/8-inch breaker bar to release the tensioner.

1. Safety First: Ensure the engine is off and cool. Disconnect the negative battery terminal to prevent accidental starts.
2. Document Routing: As mentioned, take several photos of the existing belt's routing before you begin.
3. Locate Tensioner: Identify the automatic tensioner pulley. It will have a square opening for your serpentine belt tool or breaker bar.
4. Release Tension: Insert your tool into the square opening on the tensioner. Slowly rotate the tensioner to release the belt tension. This will allow you to slip the belt off the pulleys.
5. Remove Old Belt: Carefully remove the old belt from all the pulleys, paying attention to its path.
6. Inspect Pulleys: While the belt is off, inspect all pulleys for any signs of wear, wobbling, or excessive play. Ensure they spin freely.
7. Install New Belt: Route the new belt exactly as depicted in your photos or the routing diagram provided. Save the tensioner for last. Once the belt is around all other pulleys, use your tool to release the tensioner again and slip the belt onto its final pulley.
8. Verify Routing: Double-check that the belt is correctly seated in all pulley grooves and that the routing matches your diagram.
9. Restore Power & Test: Reconnect the negative battery terminal. Start the engine and listen for any unusual noises. Allow it to run for a few minutes, then re-check the belt's alignment and tension.

Replacement Interval

Honda typically recommends inspecting the serpentine belt at each service interval and replacing it if signs of wear are present. Generally, for the 2018 Honda Pilot, a serpentine belt can last anywhere from 60,000 to 100,000 miles, or about 5 to 7 years, depending on driving conditions and maintenance. However, it's always best to consult your owner's manual for specific recommendations or have a trusted technician inspect it regularly.

Signs of a Failing Belt or Tensioner

Ignoring a failing serpentine belt or tensioner can lead to a breakdown, as critical systems like the alternator, power steering, and A/C can stop working.

Signs of a Failing Serpentine Belt:

• Squealing or Chirping Noises: This is one of the most common signs, especially on cold starts or when turning the steering wheel (power steering load).
• Cracks, Fraying, or Glazing: Visually inspect the belt. Cracks on the ribbed side, frayed edges, or a shiny, glazed appearance indicate wear.
• Loss of Power Steering: A failing belt can cause the power steering pump to lose power assist, making steering difficult.
• Overheating Engine: If the water pump isn't driven correctly by the belt, the engine can overheat.
• Battery Not Charging: A failing belt can prevent the alternator from charging the battery, leading to a dead battery.
• A/C Not Working: If the A/C compressor isn't driven, the air conditioning system will not produce cold air.

Signs of a Failing Automatic Tensioner:

• Excessive Belt Noise: A bad tensioner can cause the belt to make more noise due to improper tension.
• Belt Slippage: The belt may slip if the tensioner isn't applying enough force.
• Wobbly or Misaligned Pulley: The tensioner pulley itself might wobble or be visibly misaligned.
• Loose Belt: If the belt feels noticeably loose when the engine is off, the tensioner might be weak.

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