2015 GMC Acadia Serpentine Belt Routing & Replacement Guide

Quick Answer

For the 2015 GMC Acadia (with 3.6L V6 engine):

• Belt Length: 105.7 inches (2685 mm)
• Rib Count: 6-rib
• OEM Belt PN: AC Delco 6K1058 (or equivalent)
• Aftermarket Cross-references:
  • Gates K061058
  • Dayco 5061058
  • Continental Elite 4061058
• Auto-Tensioner PN: Gates 38159 (or equivalent)
• Idler Pulley PN: Gates 36173 (or equivalent) (Verify for your specific vehicle and accessories)

Belt Routing

The serpentine belt on your 2015 GMC Acadia, equipped with the 3.6L V6 engine, follows a specific path to drive various accessories. Before you begin any work, always take a photograph of the current belt routing. This will serve as an invaluable reference during reinstallation.

Here's a textual description of the routing, starting from the crankshaft pulley:

1. Crankshaft Pulley: The belt originates from the bottom and front of the engine, wrapping around the crankshaft pulley, which powers all other accessories.
2. A/C Compressor Pulley: From the crankshaft, the belt typically travels upwards and to the passenger side, engaging the A/C compressor pulley.
3. Idler Pulley: After the A/C compressor, the belt usually goes over an idler pulley, which helps maintain tension and guide the belt.
4. Alternator Pulley: From the idler pulley, the belt typically routes upwards and towards the driver's side, wrapping around the alternator pulley.
5. Power Steering Pump Pulley: The belt then proceeds to the power steering pump pulley, often located above or to the side of the alternator.
6. Water Pump Pulley: Next, the belt typically wraps around the water pump pulley, which is crucial for engine cooling.
7. Automatic Tensioner: Finally, the belt completes its journey by passing over or under the automatic tensioner pulley, which provides constant tension to the belt system.

Note: This routing is a general guide for the 3.6L V6 engine. Minor variations can occur based on specific vehicle options or accessory configurations. Always refer to your vehicle's owner's manual or a service manual for the exact diagram.

How to Replace the Serpentine Belt

Replacing the serpentine belt on your 2015 GMC Acadia can be a DIY task if you're comfortable with basic automotive maintenance. Here's a general overview of the steps:

1. Safety First: Ensure the engine is off and cool. Disconnect the negative battery terminal to prevent accidental starts.
2. Locate the Tensioner: Identify the automatic belt tensioner. It will have a square opening, typically 3/8-inch, where you can insert a serpentine belt tool or a breaker bar.
3. Relieve Tension: Insert a serpentine belt tool or a 3/8-inch breaker bar into the square opening of the tensioner. Rotate the tensioner to relieve tension on the belt. This will allow you to remove the old belt.
4. Remove Old Belt: While holding the tensioner in the loosened position, carefully slip the old belt off the pulleys.
5. Inspect Pulleys: Before installing the new belt, inspect all pulleys for any signs of wear, damage, or excessive play. Ensure they spin freely without resistance or noise.
6. Install New Belt: Route the new belt according to your previous photograph or the diagram in your service manual. Start by placing the belt around all smooth pulleys first, then carefully guide it over the ribbed pulleys. The last pulley to route should generally be a smooth one that is easy to access.
7. Release Tensioner: Once the belt is correctly routed, slowly release the tensioner to apply tension to the new belt.
8. Double-Check Routing: Visually inspect to ensure the belt is seated correctly in all grooves of the ribbed pulleys and is not twisted anywhere.
9. Reconnect Battery: Reconnect the negative battery terminal.
10. Test: Start the engine and listen for any unusual noises. Let it run for a few minutes and re-check the belt routing.

Replacement Interval

Most manufacturers recommend inspecting the serpentine belt at every oil change and replacing it every 60,000 to 100,000 miles, or sooner if signs of wear are present. Consult your Acadia's owner's manual for the precise recommended maintenance schedule.

Signs of a Failing Belt or Tensioner

Ignoring a worn serpentine belt or a failing tensioner can lead to serious issues, as these components drive critical systems like power steering, the alternator, and the water pump. Here are common signs to watch out for:

Serpentine Belt Issues:

• Squealing or Chirping Noises: This is often the most common symptom, especially during cold starts or when the engine is under load. It indicates slippage due to wear, improper tension, or contamination.
• Cracks, Fraying, or Glazing: Visually inspect the belt. Deep cracks, frayed edges, missing chunks, or a shiny, glazed appearance on the ribbed side are clear indicators of wear.
• Loss of Power Steering: If the belt is slipping or broken, you'll lose power steering assistance.
• Overheating: A broken or slipping belt will stop the water pump, leading to engine overheating.
• Battery Not Charging (Discharge Light): A broken or slipping belt will prevent the alternator from charging the battery.
• A/C Not Working: The A/C compressor will not function without the belt.

Tensioner Issues:

• Noise: A failing tensioner can produce rattling, grinding, or squealing noises, especially if the bearing is worn.
• Excessive Vibrations: A faulty tensioner might vibrate excessively, which can be seen and sometimes felt.
• Belt Looseness or Wobble: If the tensioner is not applying adequate tension, the belt might appear loose or wobble, particularly when the engine is running.
• Lack of Tension: If you can easily twist the belt more than 90 degrees in the longest span between pulleys, the tensioner might be weak.

If you notice any of these symptoms, it's crucial to inspect and replace the serpentine belt and/or tensioner promptly to avoid breakdowns and potential damage to other components.

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