Idler Pulley

This procedure covers the removal and replacement of the serpentine belt idler pulley on the 2015-2020 Ford F-150 with the 5.0L Coyote V8 engine.

Warnings

Tools required

Parts

• Serpentine belt idler pulley × 1 — Use OEM specification

Preparation

1. Ensure engine is completely cool to the touch
2. Park vehicle on level surface and engage parking brake
3. Open hood and secure with prop rod
4. Photograph or sketch serpentine belt routing for reinstallation reference
5. Verify adequate lighting and access to front of engine compartment

Procedure

1. 1

   Locate idler pulley and belt tensioner
   From the front of the vehicle, identify the idler pulley. On the 5.0L Coyote engine, the idler pulley is located on the passenger side of the engine block, below the alternator. The belt tensioner is positioned above and slightly forward of the idler pulley. Confirm which pulley requires replacement - the idler pulley rotates freely and does not have a spring mechanism.
2. 2

   Release belt tensioner
   Insert a 3/8" drive breaker bar into the square drive hole on the belt tensioner arm. Rotate the tensioner clockwise (toward the passenger side) to release tension on the serpentine belt. This requires approximately 40-50 lbs of force. Hold the tensioner in the released position.
3. 3

   Remove serpentine belt
   While maintaining tension on the belt tensioner with the breaker bar, slip the serpentine belt off the nearest pulley (typically the alternator or water pump). Slowly release tension on the tensioner and remove the breaker bar. Remove the belt from all remaining pulleys and extract it from the engine compartment. Inspect belt condition for wear.
4. 4

   Remove idler pulley bolt
   Using a 15mm socket and ratchet, remove the single bolt securing the idler pulley to the engine block mounting bracket. The bolt threads into a fixed bracket on the engine. Turn counterclockwise to remove. Note the orientation and any spacers or washers behind the pulley.
5. 5

   Remove idler pulley
   Pull the idler pulley straight off the mounting bracket stud or bolt hole. Inspect the mounting surface on the engine bracket for any damage, corrosion, or debris. Clean the mounting surface with a wire brush or clean rag if necessary.
6. 6

   Inspect and prepare new pulley
   Verify the new idler pulley matches the original in size, width, and mounting configuration. Check that the pulley bearing spins freely without roughness, grinding, or lateral play. Confirm the mounting bolt threads are clean and free of corrosion.
7. 7

   Install new idler pulley
   Position the new idler pulley onto the mounting bracket, ensuring proper alignment with the bolt hole. Install the idler pulley bolt by hand, threading it clockwise until finger-tight. Verify the pulley sits flush against the mounting bracket and rotates freely without binding.
   Torque spec

   Idler Pulley Bolt45 Nm (33 lb-ft)
8. 8

   Torque idler pulley bolt
   Using a torque wrench and 15mm socket, tighten the idler pulley bolt to 45.0 Nm (33.0 lb-ft). Ensure the pulley remains properly seated during torquing. After torquing, verify the pulley still rotates freely by hand.
   Torque spec

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

   Route serpentine belt
   Following your reference photo or the belt routing diagram on the radiator shroud, route the serpentine belt around all pulleys EXCEPT the final pulley (typically alternator or water pump). Ensure the belt ribs are properly seated in each pulley groove. Double-check routing against the diagram - incorrect routing will cause belt damage or component failure.
10. 10

    Install belt onto final pulley
    Insert the breaker bar into the belt tensioner and rotate clockwise to release tension. While holding the tensioner, stretch the belt over the final pulley, ensuring proper rib engagement. Slowly release the tensioner to apply proper tension to the belt. Remove the breaker bar.
11. 11

    Verify belt alignment and tension
    Visually inspect the entire belt path to confirm the belt is centered on all pulleys and properly seated in all grooves. The belt should not be riding on pulley edges or twisted. Manually rotate the crankshaft pulley two complete revolutions by hand (clockwise only) and watch for belt tracking or alignment issues. Verify the belt returns to proper position on all pulleys.

Reassembly

1. No disassembly of other components was required for this procedure

Verification

• Start the engine and listen for unusual squealing, chirping, or grinding noises from the belt area
• Observe belt operation for 30-60 seconds to ensure proper tracking and no slippage
• Verify all accessories (alternator, A/C compressor, water pump) are operating normally
• Check that the new idler pulley rotates smoothly without wobble or noise
• Confirm the idler pulley bolt remains tight after initial engine operation
• Re-inspect belt routing matches the diagram exactly

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