2016 Ram 3500 Serpentine Belt: Routing, Length, & Replacement Guide

Quick Answer

For your 2016 Ram 3500, the serpentine belt system can vary slightly depending on your engine. We'll focus on the most common configurations.

6.7L Cummins Diesel Engine

• Belt Length: Approximately 106 inches
• Rib Count: 8-rib
• OEM Belt PN: 68041549AB (Mopar)
• Aftermarket Cross-references:
  • Gates K081060
  • Dayco 5081060
  • Continental Elite 4081060
• Auto-Tensioner PN: 68060389AA (Mopar) / Gates 38407 / Dayco 89407
• Idler Pulley PN: 68028741AA (Mopar) / Gates 36199 / Dayco 89201

5.7L Hemi V8 Engine

• Belt Length: Approximately 78-79 inches (depends on specific accessory configuration)
• Rib Count: 6-rib
• OEM Belt PN: 53013697AA (Mopar) - Verify with your VIN
• Aftermarket Cross-references:
  • Gates K060787 (Check length for your specific configuration)
  • Dayco 5060787 (Check length for your specific configuration)
  • Continental Elite 4060787 (Check length for your specific configuration)
• Auto-Tensioner PN: 4627038AB (Mopar) / Gates 38328 / Dayco 89328
• Idler Pulley PN: 53013699AB (Mopar) / Gates 36248 / Dayco 89053

Belt Routing

Before you begin, always take a clear photograph of your existing serpentine belt routing path. This is the best way to ensure correct reinstallation, as variations can exist even within the same model year and engine combination due to different accessory options (e.g., dual alternators).

Here's a general description of the routing path for the 6.7L Cummins diesel, which is common for Ram 3500 heavy-duty applications. The Hemi routing will follow a similar principle but with different component placements.

1. Crankshaft Pulley: The main driving pulley, located at the bottom center of the engine. The belt will typically start here, making a significant wrap around it.
2. A/C Compressor Pulley: From the crankshaft, the belt often routes up to the air conditioning compressor pulley, usually located on the lower passenger side of the engine.
3. Idler Pulley(s): After the A/C compressor, the belt will route around one or more idler pulleys. These pulleys are smooth and are used to guide the belt and maintain tension. Note their exact position, as some engines may have multiple idlers.
4. Alternator Pulley: The belt will typically route over or under the alternator pulley, which is often found higher up on the engine, supplying power to your truck's electrical system and charging the battery.
5. Power Steering Pump Pulley: Next, the belt usually engages the power steering pump pulley, commonly located on the upper driver's side, powering your steering assist.
6. Water Pump Pulley: The belt will then wrap around the water pump pulley, which circulates coolant through your engine. This is often a critical part of the belt path, typically located centrally on the front of the engine.
7. Automatic Tensioner Pulley: Finally, the belt will pass over the automatic tensioner pulley. This spring-loaded pulley applies constant tension to the belt, ensuring proper grip and preventing slippage. The tensioner is the component you'll interact with to remove and install the belt.

How to Replace the Serpentine Belt

Tools Needed: Serpentine Belt Tool (recommended) or a 3/8-inch drive breaker bar/ratchet and appropriate socket/Torx bit for the tensioner arm, safety glasses, gloves.

1. Safety First: Ensure the engine is off and cool. Disconnect the negative battery terminal to prevent accidental starting.
2. Document Routing: Again, take a very clear photo of the existing belt routing. This is your most valuable reference.
3. Relieve Tension: Locate the automatic serpentine belt tensioner. There will be a square drive hole (typically 3/8-inch or 1/2-inch) or a hex bolt head on the tensioner arm. Insert your serpentine belt tool or breaker bar into this opening. Rotate the tool/bar in the direction that relieves tension on the belt (usually clockwise or counter-clockwise, depending on the engine and tensioner design – you'll feel it release).
4. Remove Old Belt: While holding the tensioner in the loosened position, carefully slip the old belt off one of the pulleys (e.g., an idler or a smooth, easy-to-access pulley).
5. Inspect Pulleys: With the belt off, take this opportunity to spin each pulley by hand. Listen and feel for any grinding, squeaking, excessive wobble, or resistance. Any such signs indicate a failing bearing within that pulley, which should be addressed.
6. Route New Belt: Following your reference photo, carefully route the new belt around all the pulleys except for the last one you chose for installation (often the tensioner pulley itself or an easy-to-reach idler).
7. Final Installation: With the belt mostly routed, again apply tension to the tensioner with your tool. While holding it open, slip the new belt over the final pulley. Slowly release the tensioner, ensuring the belt seats properly in all the grooves of every pulley.
8. Double Check: Before starting the engine, visually inspect the belt on every pulley to ensure it's correctly seated in all grooves and not twisted. Make sure the tensioner has returned to its operating position.
9. Reconnect Battery: Reconnect the negative battery terminal.
10. Test Run: Start the engine and listen for any abnormal noises (squealing, chirping). Observe the belt for any wobbling or signs of being off-track. Let it run for a minute or two, then shut off and re-inspect.

Replacement Interval

For most modern serpentine belts on a Ram 3500, a general replacement interval is every 60,000 to 100,000 miles or every 5 to 7 years, whichever comes first. However, this is a guideline. Factors like extreme temperatures, dusty conditions, frequent heavy towing, and oil/fluid leaks can accelerate wear. It's always best to visually inspect the belt and tensioner at least once a year or during every oil change.

Signs of a Failing Belt or Tensioner

Failing Serpentine Belt

• Squealing or Chirping Noises: Especially on startup, during acceleration, or when accessories (like A/C) engage. This often indicates slippage.
• Cracks or Fraying: Visible cracks on the ribbed side of the belt, pieces of rubber missing, or frayed edges are clear indicators for replacement.
• Glazed or Shiny Ribs: The ribbed surface appearing shiny can indicate excessive slippage and hardening of the rubber.
• Loss of Accessories: If the belt breaks, your power steering, alternator (charging system), water pump (engine cooling), and A/C will stop working. You will immediately lose power steering, your battery light will come on, and your engine will begin to overheat.

Failing Belt Tensioner

• Squealing or Chirping Noises: Can also be caused by a tensioner that isn't applying adequate tension.
• Belt Wobble/Vibration: An oscillating or vibrating serpentine belt can indicate a weak tensioner that isn't holding the belt steady.
• Visible Movement of Tensioner Arm: While the engine is running, the tensioner arm should move only slightly. If it's aggressively bouncing or vibrating, the internal spring or damper may be failing.
• Rust/Corrosion: Visible rust around the tensioner's pivot point or bearing can indicate an issue.
• Indicator Mark Misalignment (if present): Some tensioners have an indicator line or arrow that shows the operating range. If it's outside this range, the tensioner may be weak.

It's recommended to replace the automatic tensioner and idler pulleys whenever you replace the serpentine belt, especially if they show any signs of wear. These components age similarly to the belt and are crucial for the belt's proper operation and lifespan.

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