2019 GMC Yukon Serpentine Belt Guide

Quick Answer

• Belt Length & Rib Count:
  • 5.3L V8 (L83): 92.5 inches (2350mm), 6-rib
  • 6.2L V8 (L86): 92.5 inches (2350mm), 6-rib
• OEM Part Numbers:
  • Serpentine Belt: GM 12658178
  • Belt Tensioner: GM 12670928
  • Idler Pulley: GM 12629094
• Aftermarket Belt Cross-References:
  • Gates: K060925
  • Dayco: 5060925
  • Continental: 4060925

Belt Routing

Before you remove the old belt, always take a clear photograph of the belt's path to ensure you can route the new one correctly. The routing for both the 5.3L and 6.2L V8 engines is the same.

Starting from the main crankshaft pulley at the bottom center of the engine, the belt travels:

1. Up and to the right, wrapping around the A/C compressor.
2. Down and around the idler pulley.
3. Up and over the alternator at the top right of the engine.
4. Across to the left, wrapping around the power steering pump.
5. Down and under the water pump.
6. Finally, up and over the belt tensioner before returning down to the crankshaft pulley.

How to Replace the Serpentine Belt

Replacing the serpentine belt on a 2019 Yukon is a straightforward task for a DIYer with the right tool. You will need a serpentine belt tool or a long-handled 3/8" drive breaker bar.

1. Locate the Tensioner: The automatic belt tensioner is located between the water pump and the A/C compressor. It has a square 3/8" drive hole in its body.
2. Release Tension: Insert the 3/8" drive square from your serpentine belt tool or breaker bar into the hole on the tensioner. Rotate the tensioner clockwise to release the tension on the belt.
3. Remove Old Belt: While holding the tensioner, carefully slip the old belt off one of the smooth pulleys, like the water pump or idler pulley. Slowly release the tensioner back to its resting position and remove the old belt completely.
4. Install New Belt: Following your reference photograph and the routing description above, begin threading the new belt around all the pulleys, saving a smooth, easily accessible pulley for last.
5. Finalize Installation: Once the belt is routed correctly on all but one pulley, apply tension to the tensioner again and slip the belt over the final pulley. Double-check that the belt is perfectly centered in the grooves of every ribbed pulley. Slowly release the tensioner, and it will automatically apply the correct tension to the new belt.

Replacement Interval

GM recommends inspecting the serpentine belt at regular service intervals. While there is no strict mileage replacement rule, it is generally advisable to replace the belt every 60,000 to 90,000 miles, or sooner if you notice any signs of wear.

Signs of a Failing Belt or Tensioner

Pay attention to these warning signs, as a failed belt will cause your vehicle to stop running and may lead to engine damage from overheating.

• Squealing or Chirping Noises: This is the most common sign of a worn belt or a failing tensioner. The noise may be constant or may change with engine RPM.
• Visible Wear: Inspect the belt for cracks, fraying, glazing (shiny surface), or missing ribs.
• Tensioner Pulley Noise: A grinding or rumbling noise from the engine bay could indicate a worn-out bearing in the tensioner or idler pulley.
• "Fluttering" Tensioner: Watch the tensioner with the engine running. If you see it vibrating or fluttering rapidly, its internal damping mechanism has likely failed, and it is not holding steady tension on the belt.

Find a trusted shop on Repairius.