Serpentine Belt Tensioner

This procedure covers the removal and replacement of the serpentine belt tensioner on the 2016-2021 Honda Civic 1.5L Turbo engine, including belt removal and installation.

Warnings

Tools required

Parts

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

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine to cool completely for at least 30 minutes
3. Disconnect negative battery terminal and wait 3 minutes for system discharge
4. Remove engine cover by pulling upward on the four corners to release clips
5. If additional access is needed, raise and support front of vehicle on jack stands and remove right front wheel and inner fender splash shield

Procedure

1. 1

   Document belt routing
   Take a clear photo of the serpentine belt routing around all pulleys including the tensioner, crankshaft, alternator, A/C compressor, and water pump. Verify routing matches the diagram on the hood sticker if present.
2. 2

   Release belt tension
   Locate the belt tensioner on the left side of the engine. Insert a 3/8-inch breaker bar or serpentine belt tool into the square 3/8-inch hole in the tensioner arm. Rotate the tensioner clockwise to compress the spring and release tension on the belt.
   ⚠Maintain firm control of the tensioner tool. The tensioner spring is strong and can snap back forcefully if the tool slips.
3. 3

   Remove serpentine belt
   While holding the tensioner in the released position, slip the belt off one of the pulleys (alternator pulley is easiest). Slowly release tension on the tensioner and allow it to return to the relaxed position. Remove the belt completely from the engine bay.
4. 4

   Inspect belt condition
   Examine the removed belt for cracks, glazing, fraying, or missing ribs. Check for oil contamination. If any wear is present or belt has more than 60,000 miles, replace with a new belt.
5. 5

   Remove tensioner mounting bolt
   Using a 14mm socket, remove the single bolt securing the belt tensioner to the engine block. The bolt is located at the pivot point of the tensioner assembly. Keep the bolt for reinstallation if in good condition.
   Torque spec

   Belt Tensioner Bolt55 Nm (41 lb-ft)
6. 6

   Remove tensioner assembly
   Pull the tensioner assembly away from the engine block. Note the orientation of the tensioner for proper installation of the replacement unit.
7. 7

   Inspect tensioner pulley
   Spin the pulley on the old tensioner to check for roughness, grinding, or wobble. Inspect the mounting surface on the engine block for debris or damage. Clean the mounting surface with a clean rag if needed.
8. 8

   Install new tensioner
   Position the new belt tensioner onto the engine block mounting point, ensuring it is oriented correctly with the tensioner arm able to swing freely. Hand-thread the tensioner bolt to prevent cross-threading.
   Torque spec

   Belt Tensioner Bolt55 Nm (41 lb-ft)
9. 9

   Torque tensioner bolt
   Using a torque wrench, tighten the belt tensioner mounting bolt to 55.0 Nm (41.0 lb-ft). Ensure the tensioner pivots smoothly after tightening.
   Torque spec

   Belt Tensioner Bolt55 Nm (41 lb-ft)
10. 10

    Route new belt
    Following your photo or the belt routing diagram, route the new serpentine belt around all pulleys EXCEPT the final pulley (typically the alternator). Ensure the ribbed side of the belt contacts all grooved pulleys correctly.
11. 11

    Install belt on final pulley
    Using the 3/8-inch breaker bar, rotate the tensioner clockwise to release tension. Slip the belt onto the final pulley, ensuring it is properly seated in all pulley grooves. Slowly release the tensioner to apply proper tension to the belt.
    ⚠Double-check that the belt is correctly seated in all pulley grooves before releasing the tensioner. A misrouted belt can fail immediately upon engine start.
12. 12

    Verify belt installation
    Visually inspect the entire belt path to confirm the belt is properly seated on all pulleys with ribs engaged in grooves. The belt should have no twists and run straight on each pulley. Compare to your routing photo to verify accuracy.

Reassembly

1. Reinstall right front inner fender splash shield if removed
2. Reinstall right front wheel if removed and torque lug nuts to specification
3. Reinstall engine cover by aligning clips and pressing down firmly until all corners click into place
4. Reconnect negative battery terminal

Verification

• Start the engine and listen for unusual squealing, chirping, or grinding noises from the belt area
• Observe the belt while engine is running to ensure it tracks properly on all pulleys without slipping or vibrating excessively
• Check that all accessories operate correctly: alternator charging, A/C compressor engaging, no warning lights on dashboard
• Turn engine off and recheck belt tension by pressing on the longest belt span - it should deflect approximately 1/4 to 1/2 inch with moderate finger pressure
• Inspect for any coolant, oil, or fluid leaks that may have been disturbed during the repair

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

Chasing one of these codes and not sure which part is guilty? Ask a master mechanic about YOUR car →

More procedures for this vehicle