2014 GMC Sierra 2500HD: Serpentine Belt Routing & Replacement

Quick Answer

• Belt Length: 101.0 inches (2565 mm)
• Rib Count: 8-rib
• OEM Belt Part Number: 12658175
• Aftermarket Cross-References:
  • Gates: K081010
  • Dayco: 5081010
  • Continental Elite: 4081010
• Auto-Tensioner Part Number: 12670928
• Idler Pulley Part Number: 12626023

Belt Routing

Before you remove the old belt, we strongly recommend taking a clear photograph of the belt's path for reference. The serpentine belt on the 2014 GMC Sierra 2500HD with the 6.0L V8 engine follows this path:

1. Starts at the crankshaft pulley at the bottom center.
2. Wraps up and around the A/C compressor on the upper passenger side.
3. Goes down and under the idler pulley, located just below the A/C compressor.
4. Travels up to the alternator at the top of the engine bay.
5. Crosses over to the driver's side to the power steering pump.
6. Goes down and around the water pump pulley.
7. Finally, loops under the auto-tensioner before returning to the crankshaft pulley.

How to Replace the Serpentine Belt

Replacing the serpentine belt is a manageable task for a DIYer. You will need a serpentine belt tool or a long-handled 3/8" breaker bar.

1. Safety First: Make sure the engine is cool.
2. Locate the Tensioner: The auto-tensioner is located between the water pump and the crankshaft pulley. It has a 3/8" square hole in its body.
3. Release Tension: Insert the 3/8" drive of your breaker bar or serpentine belt tool into the square hole on the tensioner. Rotate the tensioner clockwise to release the tension on the belt.
4. Remove the Old Belt: While holding the tensioner, carefully slip the old belt off one of the smooth pulleys, like the water pump or idler pulley. Then, slowly release the tensioner and remove the belt completely.
5. Install the New Belt: Following your reference photo or the routing diagram described above, thread the new belt around all the pulleys, saving a smooth, easily accessible pulley for last.
6. Apply Tension: Rotate the tensioner again and slide the belt over the final pulley. Double-check that the belt is properly seated in the grooves of every ribbed pulley. A misalignment can cause the belt to shred or fly off.
7. Final Check: Once you are certain the belt is correctly installed, slowly release the tensioner and remove the tool. Start the engine and let it run for a minute to ensure the belt is tracking correctly.

Replacement Interval

While there is no universally mandated replacement interval, a general guideline is to inspect the serpentine belt at every oil change and consider replacement every 60,000 to 90,000 miles. Driving in harsh conditions (extreme heat or cold) may require more frequent replacement.

Signs of a Failing Belt or Tensioner

Be aware of these warning signs that indicate your serpentine belt or tensioner needs attention:

• Squealing or Chirping Noises: This is the most common sign, often caused by a worn, glazed, or contaminated belt.
• Visible Wear: Look for cracks, fraying, missing ribs, or glazing on the belt's surface.
• Component Malfunction: Since the belt drives multiple accessories, a failing belt can cause issues with the A/C, power steering, or charging system (alternator).
• Tensioner Noise: A grinding or rattling noise coming from the tensioner pulley indicates a failing bearing.
• "Bouncing" Tensioner: If you see the tensioner arm vibrating or bouncing erratically while the engine is running, its internal spring is likely weak and it needs to be replaced.

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