2017 Chevrolet Silverado 2500HD: Serpentine Belt Guide

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Quick Answer: Belt & Component Part Numbers

Your 2017 Silverado 2500HD came with one of two engines: the 6.0L Vortec gasoline V8 or the 6.6L Duramax diesel V8. Parts are not interchangeable, so confirm your engine before purchasing.

For the 6.0L Vortec V8 (L96)

• Serpentine Belt Length: 92.3–92.5 inches
• Rib Count: 6-rib
• OEM Belt PN: GM 12658183
• Aftermarket Belt Refs: Gates K060923, Dayco 5060923, Continental 4060923
• Belt Tensioner PN: GM 12660127
• Idler Pulley PN: GM 12626039 (smooth)

For the 6.6L Duramax V8 (L5P)

This engine uses two belts: a main drive belt and a separate belt for the A/C compressor.

• Main Serpentine Belt Length: 104.5 inches
• Main Belt Rib Count: 8-rib
• Main Belt OEM PN: GM 12673224
• Main Belt Aftermarket Refs: Gates K081045, Dayco 5081045, Continental 4081045
• A/C Compressor Belt: GM 12658182 (This is a stretch-fit belt)
• Main Belt Tensioner PN: GM 12673226
• Idler Pulley PN: GM 12626040 (smooth)

Belt Routing

Because we can't show a diagram here, the most important step you can take before removing the old belt is to photograph the current routing with your phone. A quick photo saves you from a massive headache later. If you can't, or if the belt has already broken and flown off, follow this general path.

6.0L V8 Belt Routing

Starting from the large crankshaft pulley at the bottom center of the engine:

1. The back (smooth) side of the belt wraps up and around the water pump pulley.
2. The ribbed side goes down and under the power steering pump pulley (bottom driver's side).
3. The ribbed side continues up and around the alternator pulley (top driver's side).
4. The belt crosses over to the passenger side, where the back (smooth) side wraps under the idler pulley.
5. The ribbed side then wraps under the A/C compressor pulley (bottom passenger side).
6. Finally, the belt runs straight up to the belt tensioner arm pulley, where the back (smooth) side of the belt makes its final turn before heading back to the crankshaft pulley.

6.6L Duramax V8 Main Belt Routing

Starting from the crankshaft pulley at the bottom center:

1. The belt goes up and around the belt tensioner pulley.
2. It continues down and around the power steering pump pulley.
3. From there, it goes up and over the alternator pulley.
4. It then wraps down and around the upper idler pulley.
5. The belt then travels down to the fan pulley, wrapping up and around the cooling fan pulley.
6. Finally, it returns to the crankshaft pulley.

How to Replace the Serpentine Belt

To release the tension on the belt, you will need a serpentine belt tool or a long-handled 3/8" drive breaker bar. The automatic tensioner has a 3/8" square hole in the body or on the pulley arm.

1. Insert the 3/8" square drive of your tool into the hole on the tensioner assembly.
2. Rotate the tensioner to loosen the belt. On these engines, you will typically pull the tool toward the center of the engine.
3. While holding the tensioner, slip the belt off one of the highest and easiest-to-reach smooth pulleys, like an idler or water pump.
4. Slowly release the tensioner back to its resting position.
5. Remove the old belt completely.
6. Using your photo or the path described above, route the new belt around all the pulleys, saving a smooth, easy-to-access pulley for last.
7. Rotate the tensioner again, slide the belt over the final pulley, and double-check that the belt is properly seated in every grooved pulley.
8. Slowly release the tensioner and inspect the final installation.

Replacement Interval

Modern serpentine belts are robust. There's no longer a strict mileage-based replacement schedule, but a thorough inspection is recommended every 25,000–30,000 miles. A typical belt should last between 60,000 and 100,000 miles. Its lifespan is more dependent on age, operating conditions (heat, dirt), and the condition of the pulleys and tensioner.

Signs of a Failing Belt or Tensioner

Listen and look for these signs that your serpentine belt system needs attention:

• Squealing or Chirping: This is the classic sign of a slipping belt, which could be due to wear, fluid contamination (oil, coolant), or a weak tensioner.
• Visible Wear: Look for cracks, fraying, missing ribs, or glazing (a smooth, shiny appearance in the grooves).
• Tensioner Noise: A grinding or rattling from the tensioner pulley indicates a worn-out bearing.
• "Bouncing" Tensioner Arm: Watch the tensioner arm with the engine running. If it's vibrating or bouncing erratically instead of holding steady, the internal spring is weak and it should be replaced.
• Accessory Problems: Dimming lights (alternator), stiff steering (power steering), or engine overheating (water pump) can all be caused by a slipping or broken belt.

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