2018 GMC Yukon Serpentine Belt Routing & Replacement Guide

Quick Answer

For the 2018 GMC Yukon, the serpentine belt system can vary based on the engine. Always confirm the specific engine in your vehicle before purchasing parts.

• Belt Length (5.3L and 6.2L engines): Approximately 2240mm (88.2 inches)
• Rib Count: 6-rib
• OEM Belt PN (General Motors): 12693393 (always verify with VIN)
• Aftermarket Cross-references:
  • Gates: K060882
  • Dayco: 5060883
  • Continental Elite: 4060882
• Auto-Tensioner PN (General Motors): 12628416 (always verify with VIN)
• Idler Pulley PN (General Motors): 12604245 (always verify with VIN)

Belt Routing

The serpentine belt on your 2018 GMC Yukon winds its way through several accessories. Before you begin any work, always take a clear photograph of the existing belt routing from several angles. This will be your most valuable reference during reinstallation.

While exact routing can have minor variations based on engine and accessory options, a common path for the 2018 GMC Yukon (with the 5.3L or 6.2L V8 engines) is as follows, in a clockwise direction starting from the crankshaft:

1. From the crankshaft pulley, the belt typically travels upwards and to the right.
2. It then wraps around the A/C compressor pulley (usually located low on the passenger side).
3. From the A/C compressor, it will often go upwards to an idler pulley.
4. The belt then continues to the alternator pulley (typically high on the driver's side).
5. From the alternator, it may go down to the power steering pump pulley (usually below the alternator).
6. Next, the belt generally routes to the water pump pulley (often centrally located).
7. Finally, the belt loops around the automatic tensioner pulley, which provides the necessary tension to the system before returning to the crankshaft pulley.

Remember, this is a general guide. Your photograph will be crucial for accurate re-installation.

How to Replace the Serpentine Belt

Replacing the serpentine belt on your 2018 GMC Yukon is a manageable DIY task for many, but it requires patience and the correct tools.

1. Safety First: Ensure the engine is off and cool. Disconnect the negative terminal of the battery for added safety.
2. Locate the Tensioner: Identify the automatic belt tensioner. It will have a square opening, typically 3/8-inch or 1/2-inch, designed for a breaker bar or a specialized serpentine belt tool.
3. Release Tension: Insert a 3/8-inch breaker bar or the serpentine belt tool into the square opening on the tensioner. Rotate the tensioner counter-clockwise (or clockwise, depending on the tensioner's orientation – observe the movement to confirm) to relieve tension on the belt. Hold it in this position.
4. Remove Old Belt: While holding the tensioner open, carefully slip the old belt off one of the pulleys (often the idler pulley or smooth pulley is easiest).
5. Inspect Pulleys: With the belt removed, check all pulleys (alternator, power steering, A/C, water pump, idler, tensioner) for any signs of wear, wobble, or stiffness. They should spin freely with minimal effort and no grinding noise.
6. Route New Belt: Refer to the photograph you took earlier. Begin routing the new belt, ensuring it sits correctly in all the grooves of each ribbed pulley and smoothly over any smooth idler pulleys. The last pulley to route it over should be one that is easily accessible.
7. Re-tension and Final Check: Once the belt is almost fully routed, use your breaker bar or serpentine belt tool to again release the tension on the tensioner. Slip the belt over the final pulley. Slowly release the tensioner, ensuring the belt is seated correctly on all pulleys. Give the belt a visual inspection to make sure it's aligned in all grooves.
8. Reconnect Battery and Test: Reconnect the negative battery terminal. Start the engine and let it run for a few moments, checking for any unusual noises or belt slippage. Turn off the engine and re-check the belt routing and tension.

Replacement Interval

Automotive manufacturers generally recommend inspecting the serpentine belt at every oil change and replacing it every 60,000 to 100,000 miles, or every 5 to 7 years, whichever comes first. However, driving conditions and climate can affect its lifespan. Regular inspection for cracks, fraying, or glazing is crucial.

Signs of a Failing Belt or Tensioner

Ignoring a failing serpentine belt or tensioner can lead to serious issues, as these components drive critical accessories. Look out for these signs:

• Squealing or Chirping Noises: This is one of the most common signs. It can indicate a worn belt, misaligned pulley, or a failing tensioner. The noise might be more prominent during cold starts or when turning the steering wheel (indicating power steering pump strain).
• Cracks, Fraying, or Glazing on the Belt: Visually inspect the belt. Deep cracks, missing chunks of rubber, or a shiny, glazed appearance on the ribbed side indicate wear and reduced grip.
• Loss of Power Steering: If the power steering pump isn't being driven correctly due to a slipping or broken belt, steering will become significantly harder.
• Overheating Engine: A broken belt means the water pump won't circulate coolant, leading to rapid engine overheating.
• Battery Not Charging: The alternator won't generate power if the belt isn't driving it, leading to a dead battery.
• A/C Not Working: If the A/C compressor isn't spinning, your air conditioning won't blow cold.
• Vibrations or Wobbling from Pulleys: A failing tensioner or idler pulley might cause excessive vibration or wobble. This can also lead to premature belt wear.
• Belt Slippage: If you notice the belt is slipping, especially during acceleration or when accessories are engaged, it's a clear sign of an issue.

Don't delay in addressing these symptoms. A broken serpentine belt will leave you stranded and without essential vehicle functions.

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