2017 GMC Yukon Serpentine Belt Routing & Replacement Guide

As an ASE-certified master technician, I’ve replaced countless serpentine belts on GM’s full-size SUVs. The 2017 GMC Yukon, equipped with the robust 5.3L EcoTec3 V8 or the optional 6.2L V8, features a slightly different accessory drive setup than older generations. Notably, these engines utilize electric power steering (meaning no power steering pump on the belt route) and a separate stretch-fit belt dedicated exclusively to the A/C compressor. The primary serpentine belt (main drive belt) handles the alternator, water pump, and vacuum pump.

Below is your comprehensive reference guide for replacing the main serpentine belt on your 2017 GMC Yukon.

Quick Answer: Specifications & Part Numbers

Please note: The 5.3L and 6.2L V8 engines share identical main drive belt configurations. The A/C compressor uses a separate stretch belt located behind the main drive belt.

• Belt Length: 37.8 inches (Main Accessory Drive)
• Rib Count: 6-rib
• OEM Belt PN: ACDelco 12626222 (GM Genuine)
• Aftermarket Cross-References: Gates K060378, Dayco 5060378, Continental Elite 4060378
• Auto-Tensioner PN: ACDelco 12658251 / Gates 39352
• Idler Pulley PN: ACDelco 12669569 (Note: Gen V V8s primarily rely on the tensioner pulley for routing; verify exact idler configuration based on RPO codes).

Belt Routing

Because these Gen V V8 engines utilize electric power steering and a separate A/C stretch belt, the primary serpentine belt routing is highly simplified. However, always take a photograph of your existing belt before removal to ensure you have a visual reference.

If your belt is already missing or shredded, follow this text-based step-by-step routing path:

1. Start by looping the belt around the bottom of the Crankshaft Pulley (the largest pulley at the bottom center of the engine).
2. Bring the right side of the belt straight up to wrap around the Water Pump Pulley (smooth pulley, center of the engine).
3. From the water pump, route the belt up and over the ribbed Alternator Pulley (top driver's side).
4. Bring the belt straight down from the alternator to wrap around the inside of the Auto-Tensioner Pulley (driver's side, below the alternator).
5. Finally, pull the belt back over to the starting point at the Crankshaft Pulley.

(Note: If you need to replace the A/C compressor belt, you must remove this primary belt first. The A/C belt loops strictly around the crankshaft and the A/C compressor on the lower passenger side and requires a specialized stretch-belt installation tool).

How to Replace the Serpentine Belt

Replacing the main drive belt on a 2017 GMC Yukon is an excellent DIY project that takes less than 15 minutes.

1. Locate the tensioner: The automatic belt tensioner is located on the driver’s side of the engine block, just below the alternator.
2. Release the tension: Insert a dedicated serpentine belt tool or a standard 3/8" drive breaker bar directly into the square slot on the front of the tensioner arm. Rotate the tensioner clockwise (towards the passenger side) to relieve tension on the belt.
3. Remove the old belt: While holding the tensioner open, slip the old belt off the alternator pulley. Carefully release the tensioner back to its resting position and pull the old belt out of the engine bay.
4. Install the new belt: Route the new belt following the path described above (Crank → Water Pump → Alternator), leaving the tensioner for last.
5. Apply tension: Rotate the tensioner clockwise again, slip the belt onto the tensioner pulley, and slowly release the breaker bar until the tensioner fully engages the belt. Check that all ribs are seated correctly in the pulley grooves.

Replacement Interval

Modern serpentine belts are made from durable EPDM (Ethylene Propylene Diene Monomer) rubber. Unlike older neoprene belts, they don't easily crack, but they do suffer from material loss (similar to tire tread wear).

• Inspection: Inspect every 15,000 miles. Use a belt wear gauge to check rib depth.
• Replacement: General replacement is recommended between 60,000 and 90,000 miles. Always replace the auto-tensioner at the same time as the belt, as the internal spring fatigues at the same rate the belt wears out.

Signs of a Failing Belt or Tensioner

Don't wait for a breakdown to service your accessory drive. Keep an ear and eye out for these common warning signs:

• Squealing or Chirping: Often indicates a loose belt, a failing tensioner spring, or a misaligned pulley.
• Whirring or Grinding Noises: Typically points to a failing bearing inside the tensioner pulley, idler, or alternator.
• Visible Wear: Look for missing ribs, frayed edges, or heavy glazing (a shiny appearance) on the belt's ribbed side.
• Overheating or Battery Issues: If the belt slips or breaks, the water pump and alternator stop spinning, leading to immediate engine overheating and a dead battery.
• Tensioner Bounce: With the engine running, observe the tensioner arm. If it is bouncing erratically, the internal damping mechanism has failed and the tensioner must be replaced.

If you aren't comfortable doing this job yourself, or if you suspect your A/C stretch belt also needs replacement, don't risk damaging your pulleys. Find a trusted shop on Repairius.