2024 Peterbilt 579 Serpentine Belt Routing & Part Numbers

Quick Answer

• Belt Length: TBD (Varies by engine and accessories)
• Rib Count: TBD (Typically 8-rib or 10-rib for heavy-duty trucks)
• OEM Belt PN: TBD (Varies by engine and accessories)
• Aftermarket Cross-references:
  • Gates: KXXXXXX (Please verify with Gates catalog based on specific engine)
  • Dayco: XXXXX (Please verify with Dayco catalog based on specific engine)
  • Continental Elite: XXXXX (Please verify with Continental catalog based on specific engine)
• Auto-Tensioner PN: TBD (Varies by engine and accessories)
• Idler Pulley PN: TBD (Varies by engine and accessories)

Note: The 2024 Peterbilt 579 platform can be equipped with various engine options (e.g., PACCAR MX-11, MX-13, Cummins X15), which significantly impacts serpentine belt length, rib count, and associated part numbers. Always verify part numbers based on your specific truck's engine and accessory configuration.

Belt Routing

Before you begin any work, it is crucial to photograph the existing belt routing from several angles. This will serve as an invaluable reference during reinstallation.

The serpentine belt on a Peterbilt 579 typically snakes around a series of pulleys, driving essential accessories. While specific routing will vary slightly depending on your engine and accessory load, a common path for a heavy-duty truck engine with the listed accessories might be as follows:

1. Begin at the Crankshaft Pulley (the largest pulley at the bottom, directly driven by the engine).
2. From the Crankshaft Pulley, the belt often routes up and to the left (or right, depending on engine orientation) to the A/C Compressor Pulley.
3. Leaving the A/C Compressor, the belt may then go to an Idler Pulley, which helps guide and maintain tension in the belt.
4. From the Idler Pulley, it continues to the Alternator Pulley, which recharges the battery and powers the electrical system.
5. Next, the belt wraps around the Power Steering Pump Pulley.
6. After the Power Steering Pump, it often goes to the Water Pump Pulley, which circulates coolant through the engine.
7. Finally, the belt reaches the Automatic Tensioner Pulley. This pulley pivots to apply the correct tension to the belt, ensuring proper operation of all accessories.

Remember, this is a generalized description. Always refer to your truck's specific under-hood diagram or your previously taken photographs for the exact routing.

How to Replace the Serpentine Belt

Replacing a serpentine belt on a Peterbilt 579 is a job that can be tackled by a competent mechanic. Here's a general outline:

1. Safety First: Ensure the engine is off and cool. Disconnect the negative battery terminal to prevent accidental starting.
2. Locate the Tensioner: Identify the automatic belt tensioner. It will have a square hole (typically 3/8-inch or 1/2-inch, depending on the tool needed) designed for a breaker bar or a specialized serpentine belt tool.
3. Relieve Tension: Insert the appropriate end of your serpentine belt tool or a breaker bar into the tensioner's square hole. Apply steady leverage to rotate the tensioner, relieving the pressure on the belt.
4. Remove the Old Belt: While holding the tensioner in the loosened position, carefully slip the belt off one of the pulleys (usually one of the idlers or the smooth tensioner pulley itself).
5. Inspect Pulleys: With the belt off, take this opportunity to visually inspect all pulleys for any signs of wear, wobbling, or excessive noise when spun by hand. Check for play in the automatic tensioner.
6. Install the New Belt: Following your routing diagram or photographs, begin winding the new belt around all pulleys, leaving one pulley (typically one of the smooth idlers or the tensioner pulley) free. Ensure the V-ribs of the belt align correctly with the grooves on the grooved pulleys.
7. Final Tensioning: Once the belt is almost entirely routed, use your serpentine belt tool or breaker bar to again pivot the tensioner, creating slack. Route the belt over the last pulley. Slowly release the tensioner, allowing it to spring back and apply proper tension to the belt.
8. Double-Check: Visually inspect the entire belt path to confirm it is correctly seated on all pulleys and that no ribs are off track. Reconnect the battery.
9. Test Run: Start the engine and listen for any abnormal noises (squealing, chirping). Observe the belt