This procedure covers removal and installation of the harmonic balancer (crankshaft damper) on the 3.5L EcoBoost V6 engine, requiring removal of the serpentine belt and accessory components for access.

Warnings

Tools required

Parts

• Harmonic balancer × 1 — Use OEM specification
• Harmonic balancer bolt × 1 — TTY bolt - replace if specified
• Serpentine belt (if damaged) × 1 — Use OEM specification

Preparation

1. Disconnect negative battery terminal and wait 5 minutes for airbag system to discharge
2. Raise and secure the front of the vehicle on jack stands
3. Remove engine undershield/splash shield for access to crankshaft pulley area
4. Place vehicle in Park (automatic) with parking brake engaged
5. Take a photo or mark the serpentine belt routing for reinstallation reference

Procedure

1. 1

   Remove serpentine belt
   Rotate the belt tensioner clockwise using a breaker bar or serpentine belt tool to release tension. Remove the serpentine belt from all pulleys and remove from engine bay. Inspect belt for wear, cracks, or glazing and replace if necessary.
2. 2

   Remove crankshaft pulley
   Remove the bolts securing the crankshaft pulley to the harmonic balancer. On the 3.5L EcoBoost, typically 4-6 bolts secure the pulley. Remove the pulley to expose the harmonic balancer center bolt.
   Torque spec

   Crankshaft Pulley Bolt180 Nm (133 lb-ft)
3. 3

   Secure crankshaft from rotation
   Install a crankshaft holding tool or flywheel locking tool to prevent the crankshaft from rotating. This may require accessing the transmission bellhousing area from underneath. Alternatively, use a strap wrench on the balancer itself if applicable, though a flywheel lock is preferred.
   ⚠️Do not attempt to loosen the harmonic balancer bolt without properly securing the crankshaft
4. 4

   Remove harmonic balancer bolt
   Using a breaker bar or impact wrench, remove the harmonic balancer center bolt. This bolt is very tight (180 Nm) and may require significant force. Turn counterclockwise to remove. Once loose, remove the bolt completely and retain if reusable (check service manual for TTY specification).
   ℹ️This bolt is often TTY and should not be reused - verify specification
   Torque spec

   Harmonic Balancer Bolt180 Nm (133 lb-ft)
5. 5

   Install harmonic balancer puller
   Thread a proper harmonic balancer puller onto the balancer. Use only a bolt-through-center type puller designed for this application. The center bolt threads into the crankshaft while the outer portion pulls against the balancer face. Do not use jaw-type pullers as they will damage the balancer.
   ⚠Using the wrong type of puller will destroy the harmonic balancer
6. 6

   Remove harmonic balancer
   Slowly tighten the puller center bolt while ensuring even pressure on the balancer. The balancer will gradually slide off the crankshaft snout. Once free, remove the puller and balancer from the crankshaft. Inspect the crankshaft snout for damage, burrs, or scoring.
7. 7

   Clean and inspect crankshaft snout
   Clean the crankshaft snout with a wire brush and clean rag, removing any debris, corrosion, or oil. Inspect the keyway for damage. Check the oil seal behind the balancer for leaks - if leaking, now is the ideal time to replace the front crankshaft seal. Clean the balancer mating surface.
8. 8

   Prepare new harmonic balancer
   Inspect the new harmonic balancer for any shipping damage. Verify the keyway aligns properly. Lightly oil the crankshaft snout and the inner bore of the balancer with clean engine oil to prevent galling during installation. Align the balancer keyway with the crankshaft key.
9. 9

   Install harmonic balancer
   Using a harmonic balancer installation tool (threaded installer that pulls the balancer onto the crank), carefully install the new balancer. Thread the installer into the crankshaft and slowly draw the balancer onto the snout. Never hammer the balancer on. Continue until the balancer is fully seated against the crankshaft timing gear. Remove the installation tool.
   ⚠Never use a hammer to install the harmonic balancer - this will damage internal components
10. 10

    Install and torque harmonic balancer bolt
    Install the new (or reusable if verified) harmonic balancer bolt. With the crankshaft still secured, torque the bolt to 180 Nm (133 lb-ft). If the bolt is TTY, follow the service manual specification which may include an additional angle torque step. An impact wrench may be required to achieve proper torque.
    ℹ️Verify with service manual if additional angle torque is required after initial torque
    Torque spec

    Harmonic Balancer Bolt180 Nm (133 lb-ft)
11. 11

    Reinstall crankshaft pulley
    Position the crankshaft pulley onto the harmonic balancer, aligning all bolt holes. Install the pulley bolts and torque to 180 Nm (133 lb-ft) in a star pattern to ensure even seating. Verify the pulley is flush against the balancer.
    Torque spec

    Crankshaft Pulley Bolt180 Nm (133 lb-ft)
12. 12

    Reinstall serpentine belt
    Route the serpentine belt according to the diagram (or photo taken during removal) around all pulleys. Rotate the tensioner clockwise and slide the belt onto the final pulley. Release the tensioner to apply proper tension. Verify the belt is properly seated in all pulley grooves.
13. 13

    Final reassembly
    Reinstall the engine undershield/splash shield. Remove jack stands and lower the vehicle. Reconnect the negative battery terminal. Remove any tools or holding devices from the engine bay.

Reassembly

1. Ensure all bolts are torqued to specification in the proper sequence
2. Verify serpentine belt is properly routed and seated on all pulleys
3. Double-check that all tools have been removed from the engine bay
4. Confirm no leaks are present at the front crankshaft seal area

Verification

• Start the engine and listen for unusual noises from the front of the engine
• Verify the harmonic balancer rotates smoothly without wobble or vibration
• Check for serpentine belt proper tracking - belt should not walk off pulleys
• Inspect for oil leaks around the crankshaft seal after 5 minutes of idle
• Test drive the vehicle and monitor for vibrations, especially at idle and low RPM

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