2020 GMC Acadia Serpentine Belt

Quick Answer

• Belt Length and Rib Count: 152.07 cm, 6-rib
• OEM Belt Part Number: 12658145
• Aftermarket Cross-References: Gates K060600, Dayco 5060600, Continental Elite 4060600
• Automatic Tensioner Part Number: 12670921
• Idler Pulley Part Number: 12686759

Belt Routing

Before removing the old serpentine belt, it is crucial to either find a belt routing diagram for your specific engine or take a clear photograph of the existing belt's path. This will serve as a vital reference during reinstallation.

The serpentine belt on the 2020 GMC Acadia with the 3.6L V6 engine follows this path:

1. Crankshaft Pulley: The belt wraps around the crankshaft pulley at the bottom of the engine.
2. Air Conditioning (A/C) Compressor: From the crankshaft pulley, the belt moves up to the A/C compressor.
3. Idler Pulley: Next, it goes around the idler pulley.
4. Alternator: Then, the belt routes to the alternator.
5. Power Steering Pump: After the alternator, it wraps around the power steering pump.
6. Water Pump: The belt then goes to the water pump.
7. Tensioner: Finally, the belt makes its way to the tensioner before returning to the crankshaft pulley.

How to Replace the Serpentine Belt

Replacing the serpentine belt on a 2020 GMC Acadia is a manageable task for a DIYer with the right tools. The key is to release the tension on the belt using the automatic tensioner.

You will need a serpentine belt tool or a long-handled 3/8" drive breaker bar. Insert the square drive of the tool into the corresponding square hole on the automatic tensioner arm. Rotate the tensioner to loosen the belt, and then carefully slip the belt off one of the pulleys. Once the old belt is off, use your belt routing diagram or photograph to install the new belt, ensuring it is properly seated in all the pulley grooves. Finally, release the tensioner to tighten the new belt.

Replacement Interval

For the 2020 GMC Acadia, it is recommended to inspect the serpentine belt at regular service intervals and replace it every 60,000 to 100,000 miles, or as needed. Factors such as climate and driving conditions can affect the belt's lifespan. Consult your owner's manual for the specific replacement interval recommended by GMC.

Signs of a Failing Belt or Tensioner

A failing serpentine belt or tensioner will often provide warning signs. Be aware of the following:

• Squealing or Chirping Noises: This is one of the most common signs of a worn or loose belt.
• Visible Wear and Tear: Inspect the belt for cracks, fraying, glazing, or missing ribs.
• Accessory Malfunctions: A failing belt can cause issues with the alternator, power steering, air conditioning, and water pump.
• Tensioner Pulley Noise: A grinding or rattling noise from the tensioner area can indicate a failing bearing in the tensioner pulley.
• Excessive Belt Vibration: A worn tensioner may not be able to maintain the proper belt tension, leading to visible belt flapping or vibration while the engine is running.

If you notice any of these signs, it is important to have the serpentine belt and tensioner inspected and replaced as soon as possible to avoid a breakdown.

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