2023 Ford F-150 Serpentine Belt: Routing, Length & Replacement Guide

Quick Answer

For the 3.5L EcoBoost V6 Engine:

• Belt Length & Rib Count: 2100mm, 6-rib
• OEM Belt Part Number: Ford ML3Z-8620-A
• Aftermarket Cross-References:
  • Gates K060827
  • Dayco 5060825
  • Continental 4060825
• Auto-Tensioner Part Number: Ford HL3Z-6B209-B
• Idler Pulley Part Number: Ford F6AZ-8678-AAA

For the 5.0L V8 Engine:

• Belt Length & Rib Count: 1530mm, 6-rib
• OEM Belt Part Number: Ford BR3Z-8620-A
• Aftermarket Cross-References:
  • Gates K060595
  • Dayco 5060595
  • Continental 4060595
• Auto-Tensioner Part Number: Ford 9L3Z-6B209-A
• Idler Pulley Part Number: Ford F6AZ-8678-AAA

Belt Routing

Properly routing the serpentine belt is critical for the function of your F-150’s engine accessories. Because routing diagrams can vary slightly based on options, it is essential to photograph the existing belt path before you begin removal. This will serve as your most accurate guide.

For a typical 2023 F-150, the belt follows a path similar to this:

1. Crankshaft Pulley: Start at the large, main pulley at the bottom of the engine.
2. A/C Compressor: From the crank, the belt moves to the air conditioning compressor.
3. Idler Pulley: Next, it routes to an idler pulley, which helps guide the belt along its path.
4. Alternator: The belt then travels up to the alternator.
5. Power Steering Pump: From the alternator, it moves to the power steering pump (on models equipped).
6. Water Pump: The belt then wraps around the water pump pulley.
7. Tensioner: Finally, the belt goes around the auto-tensioner pulley, which maintains the correct pressure on the system before returning to the crankshaft.

How to Replace the Serpentine Belt

Replacing the belt is a manageable DIY job for many owners. You will need a serpentine belt tool, which is a long, thin tool with various socket and crow’s foot attachments. In many cases, a standard 3/8" or 1/2" drive breaker bar will fit into the square hole on the auto-tensioner.

1. Locate the Tensioner: Find the automatic belt tensioner. It is a spring-loaded pulley designed to move.
2. Release Tension: Insert your breaker bar or serpentine belt tool into the designated square hole on the tensioner body. Rotate the tensioner to release the pressure on the belt. The tensioner is spring-loaded, so this will require some force.
3. Remove the Old Belt: While holding the tensioner in the released position, slip the old belt off one of the smooth, non-lipped pulleys (like the water pump or idler).
4. Install the New Belt: Following the routing path you photographed earlier, carefully thread the new belt around all the pulleys, saving a smooth, easily accessible pulley for last.
5. Finalize Installation: Release the tension on the tensioner tool again and slide the belt over the final pulley. Slowly release the tool, allowing the tensioner to apply pressure to the new belt. Double-check that the belt is correctly seated in the grooves of every pulley.

Replacement Interval

Ford recommends inspecting the serpentine belt at regular service intervals and replacing it as needed. While there is no strict replacement mileage, most modern serpentine belts have a service life of around 100,000 miles. However, this can be affected by operating conditions. A truck used for heavy towing or in extreme climates may require an earlier replacement.

Signs of a Failing Belt or Tensioner

Your truck will often give you warning signs before a belt fails completely. Ignoring them can lead to a breakdown, as the belt powers critical components like the alternator and water pump.

• Squealing or Chirping Noises: This is the most common sign. The noise may be constant or may change with engine speed or when accessories like the A/C are turned on.
• Visible Wear: Inspect the belt for cracks, glazing (a shiny, smooth appearance on the ribbed side), fraying, or missing chunks of ribbing.
• Tensioner Issues: A failing tensioner can also cause problems. Look for a tensioner arm that is vibrating excessively while the engine is running or a pulley that feels rough or makes a grinding noise when spun by hand (with the engine off).
• Accessory Malfunctions: If your battery isn’t charging properly (alternator) or the engine temperature rises (water pump), a slipping or broken belt could be the cause.

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