Alternator Belt

This procedure covers the removal and replacement of the serpentine belt (alternator belt) on the 2015-2020 Ford F-150 with 5.0L V8 Coyote engine, including proper belt routing and tension verification.

Warnings

Tools required

Parts

• Serpentine belt × 1 — Motorcraft 8K2Z6C301A or equivalent 6-rib 98.0 inch belt

Preparation

1. Allow engine to cool completely if recently operated
2. Park vehicle on level ground and engage parking brake
3. Open hood and secure with prop rod
4. Locate the belt routing diagram on the fan shroud or radiator support (photograph it if present)
5. Visually inspect the belt path from above to familiarize yourself with component locations

Procedure

1. 1

   Document belt routing
   Before removing the old belt, take a clear photo of the serpentine belt routing around all pulleys, or sketch the pattern on paper. Verify against the under-hood routing diagram if present. The belt routes around the crankshaft, water pump, alternator, A/C compressor, power steering pump, and idler pulleys.
2. 2

   Locate the belt tensioner
   The automatic belt tensioner is located on the passenger side of the engine, toward the front. It is a spring-loaded pulley assembly with a 3/8 inch square drive socket or a hexagonal bolt head for rotation. Identify the direction of rotation needed to relieve tension (clockwise when viewed from the front).
3. 3

   Release belt tension
   Insert a 3/8 inch drive breaker bar into the square hole on the tensioner arm. Rotate the tensioner clockwise (toward the passenger side) to compress the spring and relieve belt tension. The tensioner will move approximately 2-3 inches. Hold the tensioner in this position.
4. 4

   Remove the old belt
   While holding the tensioner in the released position, slip the serpentine belt off the nearest pulley (typically the alternator or idler pulley works best). Slowly release tension on the tensioner arm and allow it to return to its resting position. Remove the belt completely from all pulleys and extract it from the engine bay.
5. 5

   Inspect pulleys and tensioner
   With the belt removed, spin each pulley by hand to check for roughness, noise, or excessive play. The tensioner should hold its position and not sag. Check all pulleys for damage, wear grooves, or contamination from oil or coolant. Address any issues before installing the new belt.
6. 6

   Route the new belt
   Starting at the bottom, route the new serpentine belt around all pulleys EXCEPT the tensioner pulley, following your photo or the routing diagram. Ensure the belt ribs seat properly in each pulley groove. The flat side of the belt should contact only smooth pulleys (if any). Verify the belt path matches your documentation exactly before proceeding.
7. 7

   Install belt onto tensioner
   Using the breaker bar, rotate the tensioner clockwise again to relieve tension. While holding the tensioner, slip the belt over the tensioner pulley. Ensure the belt is properly seated in the pulley grooves. Slowly release the tensioner arm, allowing it to apply proper tension to the belt.
8. 8

   Verify belt installation
   Visually inspect the entire belt path to confirm the belt is properly seated in all pulley grooves with no twists or misalignment. The belt ribs should be centered in each grooved pulley. Compare the routing against your photo to ensure accuracy. Check that the belt does not contact any engine components, brackets, or shields.
9. 9

   Test belt operation
   Start the engine and allow it to idle. Listen for any squealing, chirping, or abnormal noises that would indicate improper belt tension or misalignment. Observe the belt operation for 30-60 seconds. If any unusual sounds occur, shut off the engine immediately and recheck belt routing and seating.

Reassembly

1. No disassembly was required for this procedure beyond belt removal
2. Ensure all tools are removed from the engine bay
3. Close and secure the hood

Verification

• Start the engine and verify smooth, quiet belt operation with no squealing or slapping sounds
• Observe the belt while idling to confirm it runs true on all pulleys without excessive vibration
• Rev the engine slightly (1500-2000 RPM) and verify the belt remains properly seated and quiet
• Check that all electrical accessories (alternator charging) function properly
• Re-inspect belt routing after the first short drive to confirm proper seating under load

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