2023 GMC Yukon Serpentine Belt Routing, Length & Part Numbers

As an ASE-certified master technician, I know that replacing the serpentine belt on your 2023 GMC Yukon is a critical maintenance task that keeps your SUV’s vital accessories running smoothly. Whether you are dealing with the 5.3L V8, the 6.2L V8, or the 3.0L Duramax turbo-diesel, having the correct part numbers and understanding the belt routing will save you time and frustration.

Here is your comprehensive guide to the serpentine belt routing, specifications, and replacement procedures for the 2023 GMC Yukon.

Quick answer

Note: The following specifications are primarily for the 5.3L and 6.2L V8 engines (L84/L87). If you have the 3.0L Duramax diesel, verify exact part numbers with your supplier, as belt lengths and tensioner configurations differ significantly.

• Belt Length: 38.5 inches (Main drive belt)
• Rib Count: 6-rib
• OEM Belt PN: GM 12695507 (Main Drive)
• Aftermarket Cross-References: Gates K060388, Dayco 5060388, Continental Elite 4060388
• Auto-Tensioner PN: AC Delco 12695621
• Idler Pulley PN: AC Delco 12695622

Keep in mind that modern GM V8s often utilize a separate stretch fit belt for the A/C compressor. Always double-check your specific engine configuration.

Belt routing

Because engine bays can be incredibly cramped, and a single mistake can lead to a shredded belt, I highly recommend taking a clear photograph of your existing belt routing with your smartphone before you begin the removal process.

For a traditional full accessory drive layout, the belt routing follows this continuous path:

1. Start by looping the belt around the bottom of the Crankshaft pulley.
2. Route it up and over the A/C compressor (if integrated into the main drive).
3. Tuck it under the smooth Idler pulley.
4. Pull it up and around the Alternator.
5. Bring it down around the Power steering pump (Note: 2023 Yukons utilize Electric Power Steering, so this pulley is bypassed on standard V8s, but the traditional routing path occupies this space for older/heavy-duty configurations).
6. Route the smooth back side of the belt over the Water pump.
7. Finally, slip the final loop over the Auto-tensioner as you release the tension.

How to replace the serpentine belt

Replacing the serpentine belt on your 2023 Yukon is a manageable DIY job if you have the right tools.

1. Gather your tools: You will need a specialized serpentine belt tool or a standard 3/8" drive breaker bar.
2. Relieve tension: Locate the auto-tensioner assembly on the front of the engine block. Insert the 3/8" drive breaker bar (or serpentine belt tool) into the square slot on the tensioner arm. Rotate the tensioner to relieve the pressure on the belt.
3. Remove the old belt: While holding the tensioner open, slip the belt off the easiest accessible pulley (usually the alternator or idler pulley). Gently release the tensioner and pull the old belt out of the engine bay.
4. Route the new belt: Following your reference photo (or the routing description above), weave the new belt around all the pulleys except for the final tensioner or easily accessible idler pulley. Ensure the ribbed side of the belt sits perfectly flush in the grooves of the ribbed pulleys, and the flat side rides smoothly on the smooth pulleys.
5. Install and check: Pry the tensioner open again, slip the belt over the final pulley, and slowly release the tensioner. Double-check every pulley to ensure the belt is properly seated in the grooves.

Replacement interval

For the 2023 GMC Yukon, the serpentine belt is made of highly durable EPDM rubber. However, it still wears down over time. I recommend inspecting the belt at 60,000 miles and planning for a complete replacement between 80,000 and 100,000 miles. It is best practice to replace the auto-tensioner and idler pulley at the same time, as the bearings in these components generally have the same lifespan as the belt itself.

Signs of a failing belt or tensioner

Don't wait for the belt to snap and leave you stranded. Watch for these common warning signs:

• Squealing or Chirping: A high-pitched noise, especially on startup or when accelerating, indicates belt slip, a stretched belt, or a weak tensioner spring.
• Visible Wear: Look for fraying edges, missing chunks of ribs, or excessive cracking on the ribbed side of the belt. (Note: EPDM belts don't crack as noticeably as older neoprene belts, so use a tread depth gauge if unsure).
• Accessory Issues: If your battery light flickers, your engine starts running hot (water pump issue), or your A/C cuts out, a slipping belt could be the culprit.
• Tensioner Bounce: While the engine is idling, watch the auto-tensioner. If the arm is bouncing excessively, the internal spring or dampener has failed, and it needs immediate replacement.

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