2022 GMC Sierra 2500HD Serpentine Belt Guide

Quick Answer

• Engine Option: 6.6L V8 Gas (L8T)

  • Belt Length: 2200mm (86.6 inches)
  • Rib Count: 6-rib
  • OEM Belt Part Number: GM 12693488
  • Aftermarket Cross-References: Gates K060866, Dayco 5060865, Continental 4060866
  • Auto-Tensioner Part Number: GM 12690986
  • Idler Pulley Part Number: GM 12690987

• Engine Option: 6.6L V8 Duramax Turbo-Diesel (L5P)

  • Main Serpentine Belt:
    • Belt Length: 2470mm (97.2 inches)
    • Rib Count: 8-rib
    • OEM Belt Part Number: GM 12704153
    • Aftermarket Cross-References: Gates K080972, Dayco 5080970, Continental 4080972
    • Auto-Tensioner Part Number: GM 12677945
    • Idler Pulley Part Numbers: GM 12626023 (smooth), GM 12677946 (grooved)
  • Secondary Belt (A/C Compressor):
    • Belt Length: 1020mm (40.2 inches)
    • Rib Count: 4-rib
    • OEM Belt Part Number: GM 12690863
    • Aftermarket Cross-References: Gates K040402, Dayco 5040400
    • Tensioner: This is a stretch-fit belt and does not use a tensioner.

Belt Routing

Before you remove the old belt, always take a clear photograph of the belt's path. This will be your best guide. The routing can differ slightly based on accessory options, but the following are the most common paths.

6.6L Gas V8 (L8T) Routing Path

The single serpentine belt on the gas engine follows this general 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 to the Idler Pulley below the A/C compressor.
4. Moves across to the Alternator on the upper driver's side.
5. Comes down to the Power Steering Pump below the alternator.
6. Goes across to the Water Pump in the center.
7. Finally, loops under the Tensioner Pulley before returning to the crankshaft.

6.6L Duramax Diesel V8 (L5P) Routing Path

The Duramax engine uses two separate belts.

Main Belt:

1. Starts at the Crankshaft Pulley.
2. Wraps up to the Alternator on the upper driver's side.
3. Goes down and around the Power Steering Pump.
4. Crosses over to the Idler Pulley on the passenger side.
5. Loops up and around the Water Pump.
6. Finishes by going under the Tensioner Pulley before returning to the crank.

A/C Belt: This is a smaller, dedicated stretch-fit belt that drives only the A/C compressor from a secondary pulley on the crankshaft.

How to Replace the Serpentine Belt

Replacing the serpentine belt is a common maintenance item that requires a specific tool to release the belt tension.

1. Gather Your Tools: You will need a serpentine belt tool, which is a long, thin ratchet with various socket and crowfoot attachments. Alternatively, a long 3/8" or 1/2" drive breaker bar can often fit into the square hole on the auto-tensioner.
2. Locate the Tensioner: The auto-tensioner is a spring-loaded pulley designed to keep the belt tight. It has a square hole or a raised nut where your tool will attach.
3. Release Tension: Fit your tool onto the tensioner and pivot it to release the belt's tension. The direction of rotation depends on the engine, but you will feel the spring resistance lessen.
4. Remove the Old Belt: While holding the tensioner, slip the old belt off one of the smooth pulleys, like the water pump or idler. Then, slowly release the tensioner and remove the belt completely.
5. Route the New Belt: Carefully route the new belt around all the pulleys according to your photograph or the diagram. Leave one of the easily accessible, smooth pulleys for last.
6. Install the New Belt: Release the tensioner again and slide the new belt over the final pulley. Double-check that the belt is correctly seated in the grooves of every ribbed pulley. Slowly release the tensioner to apply pressure.
7. Final Inspection: Start the engine and watch the belt for a few seconds to ensure it is tracking correctly and not making any unusual noises.

Replacement Interval

Modern serpentine belts are durable. While there is no universally mandated replacement interval, a general guideline is to inspect the belt during every oil change and plan for replacement every 60,000 to 90,000 miles. For a heavy-duty truck that sees severe use (towing, hauling, excessive idling), it’s wise to lean toward the earlier end of that range.

Signs of a Failing Belt or Tensioner

Listen and look for these warning signs:

• Squealing or Chirping: This is the most common sign, often worse on cold starts or in damp weather. It indicates the belt is slipping.
• Visible Wear: Inspect the belt for cracks, fraying, glazing (shiny spots), or missing ribs.
• Tensioner Noise: A grinding or rattling noise from the tensioner pulley indicates a failing bearing.
• Tensioner Vibration: If you see the tensioner arm vibrating excessively while the engine is running, its internal spring is likely weak and failing to provide adequate tension.
• Accessory Malfunctions: If your power steering feels heavy or the battery light flickers, it could mean the belt is slipping and not properly driving the accessories.

If you're not comfortable performing this service yourself, you can find a trusted and certified shop in your area on Repairius.