6.7 Cummins Serpentine Belt Diagram With AC

The serpentine belt is a critical component in the 6.7 Cummins diesel engine, responsible for driving multiple accessories like the alternator, power steering pump, and air conditioning compressor. Understanding the belt routing diagram is essential for proper maintenance and replacement. This guide will provide a detailed overview of the serpentine belt diagram for 6.7 Cummins engines equipped with air conditioning.

The 6.7 Cummins serpentine belt system consists of several key components, including the crankshaft pulley, tensioner pulley, idler pulley, and various accessory pulleys. The belt follows a specific path around these pulleys to ensure optimal performance and efficiency of the engine's auxiliary systems.

Serpentine Belt Routing

The serpentine belt routing for a 6.7 Cummins engine with AC follows a specific path to ensure proper function of all accessories. Starting from the crankshaft pulley, the belt typically follows this route:

1. From the crankshaft pulley, the belt wraps around the bottom of the AC compressor pulley.

2. It then travels upward to the tensioner pulley, which maintains proper belt tension.

3. The belt makes a U-turn around the tensioner and heads back down towards the crankshaft pulley.

4. It wraps around the crankshaft pulley, making a complete circle.

5. From there, it goes up to the fan hub pulley (often mistaken for the water pump pulley).

6. The belt then makes another U-turn and goes down to the power steering pump pulley.

7. Finally, it wraps around the alternator pulley before completing its circuit back to the crankshaft.

It's important to note that the smooth side of the belt should always face the smooth pulleys, while the ribbed side contacts the grooved pulleys. This ensures proper grip and prevents slippage during operation.

Belt Tensioner

The belt tensioner plays a crucial role in maintaining proper serpentine belt function. It automatically adjusts to keep the belt at the correct tension, compensating for belt stretch and wear over time. The tensioner consists of a spring-loaded arm with a pulley at the end.

To replace the serpentine belt, you'll need to relieve the tension by rotating the tensioner. This is typically done using a 1/2-inch breaker bar or socket wrench inserted into a square hole on the tensioner. Rotating the tensioner counterclockwise will release the tension, allowing you to remove the old belt and install a new one.

Challenges in Belt Replacement

Replacing the serpentine belt on a 6.7 Cummins can present some challenges:

• Limited space: The area between the fan and crankshaft pulleys is often very tight, making it difficult to maneuver the belt.
• Tensioner access: On some models, accessing the tensioner may require removing or loosening the fan shroud.
• Belt routing: Ensuring the new belt follows the correct path around all pulleys can be tricky, especially for first-time DIYers.

To overcome these challenges, it's recommended to:

• Use a belt routing diagram as a reference during installation.
• Consider loosening the tensioner mounting bolt to create more space for belt installation.
• Take photos or mark the old belt's path before removal to aid in proper reinstallation.

Belt Maintenance and Inspection

Regular inspection of the serpentine belt is crucial for maintaining the 6.7 Cummins engine's performance and reliability. Here are some key points to consider:

• Inspect the belt every 15,000 miles or at each oil change, whichever comes first.
• Look for signs of wear, cracking, fraying, or glazing on the belt surface.
• Check for proper tension - a loose belt can cause accessory malfunction and increased wear.
• Ensure all pulleys are properly aligned and spin freely without wobble or noise.
• Replace the belt immediately if any significant damage or wear is observed.

A well-maintained serpentine belt typically lasts between 60,000 to 100,000 miles, but this can vary based on driving conditions and belt quality. Always replace the belt with a high-quality OEM or equivalent aftermarket part designed for the 6.7 Cummins engine.

Tools and Preparation

Before attempting to replace the serpentine belt on your 6.7 Cummins, gather the following tools and materials:

• New serpentine belt (ensure correct length and type for your specific model)
• 1/2-inch drive breaker bar or ratchet
• Socket set (including 13mm for possible fan shroud removal)
• Flashlight or work light
• Belt routing diagram (printed or digital)
• Safety glasses and work gloves

Preparation steps:

1. Ensure the engine is cool before beginning work.

2. Disconnect the negative battery terminal to prevent electrical hazards.

3. Remove any engine covers or shields that may obstruct access to the belt area.

4. If necessary, remove or loosen fan shroud bolts to improve access to the tensioner.

Having the correct tools and proper preparation will make the belt replacement process smoother and safer.

Replacement Procedure

Follow these steps to replace the serpentine belt on your 6.7 Cummins engine:

1. Locate the belt tensioner and insert the 1/2-inch drive tool into the square hole.

2. Rotate the tensioner counterclockwise to relieve belt tension.

3. Carefully remove the old belt, noting its routing path.

4. Inspect all pulleys for signs of wear, damage, or misalignment.

5. Route the new belt following the diagram, starting with the bottom pulleys first.

6. Work the belt between the fan and crankshaft pulleys carefully, using a rocking motion if necessary.

7. Ensure the belt is seated correctly in all pulley grooves.

8. Slowly release the tensioner, allowing it to apply proper tension to the new belt.

9. Double-check the belt routing and alignment on all pulleys.

10. Reinstall any components removed for access (fan shroud, covers, etc.).

11. Reconnect the battery and start the engine to verify proper belt operation.

After installation, run the engine for a few minutes and listen for any unusual noises. Recheck the belt tension and alignment after the first 50-100 miles of driving.

Common Issues and Troubleshooting

Even with proper installation, you may encounter some issues with the serpentine belt system. Here are some common problems and their potential solutions:

• Squealing noise: This often indicates a loose or glazed belt. Check tension and replace if necessary.
• Chirping sound: May be caused by pulley misalignment or a worn bearing. Inspect and replace affected components.
• Belt slipping: Usually due to improper tension or a worn belt. Adjust tensioner or replace the belt.
• Rapid belt wear: Can be caused by misaligned pulleys or a faulty tensioner. Inspect and replace components as needed.
• Belt coming off pulleys: Typically results from severe misalignment or a broken tensioner. Address underlying issues before installing a new belt.

If you experience persistent issues after belt replacement, consider having a professional mechanic inspect the serpentine belt system to identify any underlying problems with pulleys, bearings, or the tensioner assembly.

FAQs About 6.7 Cummins Serpentine Belt Diagram With AC

• How often should I replace the serpentine belt on my 6.7 Cummins?
  Typically, replacement is recommended every 60,000 to 100,000 miles, but inspect regularly for wear.
• Can I drive with a loose serpentine belt?
  It's not recommended, as it can cause accessory malfunction and increased wear on components.
• What causes premature serpentine belt wear on a 6.7 Cummins?
  Common causes include misaligned pulleys, faulty tensioners, and exposure to extreme temperatures or contaminants.
• How do I know if my serpentine belt tensioner is bad?
  Signs include unusual noises, excessive belt wear, or visible damage to the tensioner assembly.
• Can I replace the serpentine belt myself on a 6.7 Cummins?
  Yes, with proper tools and knowledge of the belt routing, it's a manageable DIY task for most experienced owners.