Idler Pulley

This procedure covers removal and replacement of the serpentine belt idler pulley on the 5.0L Coyote V8 engine.

Warnings

Tools required

Parts

• Idler pulley assembly × 1 — Use OEM specification
• Serpentine belt (if worn or damaged) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and set parking brake
2. Allow engine to cool completely
3. Photograph or diagram serpentine belt routing for reinstallation reference
4. Ensure adequate working space around front of engine compartment

Procedure

1. 1

   Access the serpentine belt
   Open hood and locate the serpentine belt routing diagram on the radiator support or underside of hood. The 5.0L Coyote engine has the belt system on the front of the engine. Identify the idler pulley location - it is typically a smooth pulley without ribs, separate from the belt tensioner pulley.
2. 2

   Release belt tension
   Locate the automatic belt tensioner on the passenger side of the engine. Using a serpentine belt tool or 1/2 inch breaker bar, insert into the square 1/2 inch drive hole in the tensioner arm. Rotate the tensioner clockwise to release tension on the belt. The tensioner will pivot against spring pressure.
   ⚠Maintain firm control of the tensioner tool - spring tension is strong and can cause the tool to slip
3. 3

   Remove serpentine belt
   While holding tension off the belt with the tensioner tool, slip the belt off one of the pulleys - the alternator or power steering pump pulleys work well for this. Slowly release the tensioner back to its resting position. Remove the belt from all remaining pulleys and extract from engine compartment.
4. 4

   Inspect belt condition
   Examine the serpentine belt for cracks, glazing, fraying, or missing ribs. Check for oil or coolant contamination. If belt shows wear or damage, replace it rather than reinstalling. Compare against new belt if uncertain about condition.
5. 5

   Remove idler pulley bolt
   Using a 15mm socket and ratchet, remove the center bolt securing the idler pulley to its mounting bracket. The bolt threads into a stud or threaded hole on the engine front cover. Turn counterclockwise to loosen and remove completely.
   ℹ️Note the orientation of any washers or spacers behind the pulley for correct reassembly
6. 6

   Remove old idler pulley
   Pull the idler pulley assembly straight off the mounting stud. Inspect the mounting stud for damage or thread wear. Clean the mounting surface on the engine front cover of any debris or corrosion.
7. 7

   Inspect new idler pulley
   Verify the new idler pulley matches the old unit in diameter and width. Spin the pulley bearing by hand - it should rotate smoothly without grinding, roughness, or excessive play. Check that any washers or spacers are positioned correctly.
8. 8

   Install new idler pulley
   Position the new idler pulley onto the mounting stud with any washers or spacers in their correct locations. Ensure the pulley sits flush against the mounting surface. Hand-thread the retaining bolt clockwise to prevent cross-threading.
   Torque spec

   Idler Pulley Bolt45 Nm (33 lb-ft)
9. 9

   Torque idler pulley bolt
   Using a torque wrench and 15mm socket, tighten the idler pulley bolt to 45.0 Nm (33.0 lb-ft). Verify the pulley spins freely after torquing and does not wobble or bind.
   Torque spec

   Idler Pulley Bolt45 Nm (33 lb-ft)
10. 10

    Reinstall serpentine belt
    Following the belt routing diagram, thread the serpentine belt around all pulleys except the final pulley (typically alternator or power steering). Ensure the ribbed side of the belt contacts all grooved pulleys correctly. Use the tensioner tool to rotate the tensioner clockwise and slip the belt onto the final pulley. Slowly release the tensioner to apply proper tension to the belt.
11. 11

    Verify belt alignment
    Visually inspect that the belt is seated properly in all pulley grooves and aligned correctly across all pulleys. The belt should track centered on each pulley without riding on edges. Rotate the engine by hand one full revolution using a socket on the crankshaft bolt to verify proper belt operation and alignment throughout the rotation cycle.
    ⚠Ensure no tools or hands are near moving components when rotating engine

Reassembly

1. Double-check that serpentine belt is properly seated on all pulleys
2. Verify idler pulley rotates freely without noise or binding
3. Remove all tools from engine compartment
4. Close hood securely

Verification

• Start engine and listen for unusual noises from the belt area - squealing indicates improper tension or alignment
• Observe belt operation at idle for 30-60 seconds to ensure it tracks properly on all pulleys without slipping or vibration
• Check that all accessories (alternator, power steering, A/C compressor) are functioning normally
• After initial test run, re-inspect belt alignment and idler pulley operation with engine off

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