2018 Ram 3500 Serpentine Belt: Routing, Replacement, and Part Numbers

Quick Answer

• Belt Length: Varies by engine – see OEM and aftermarket part numbers below.
• Rib Count: 6-rib (for most engines).
• OEM Belt Part Numbers:
  • 6.4L HEMI: 68060875AC
  • 6.7L Cummins Diesel: 68027608AB
• Aftermarket Cross-References (6.4L HEMI):
  • Gates: K061031 (standard), K061031RPM (heavy-duty)
  • Dayco: 5061030
  • Continental Elite: 4061030
• Aftermarket Cross-References (6.7L Cummins Diesel):
  • Gates: K061035 (standard), K061035RPM (heavy-duty)
  • Dayco: 5061035
  • Continental Elite: 4061035
• Auto-Tensioner Part Numbers:
  • 6.4L HEMI: 68060879AB
  • 6.7L Cummins Diesel: 68027611AB
• Idler Pulley Part Numbers:
  • 6.4L HEMI: 4891783AC (upper), 53013898AA (lower, if equipped)
  • 6.7L Cummins Diesel: 68027612AB

Belt Routing (Text-Based Description)

Before you begin any work, always take a photograph of your current serpentine belt routing! This will be an invaluable reference during reinstallation.

Keep in mind that the routing can be slightly different depending on your engine (6.4L HEMI or 6.7L Cummins Diesel) and specific vehicle options. The general path, however, remains similar.

For 6.4L HEMI Engine:

1. Begin at the Crankshaft Pulley (the large pulley at the bottom central part of the engine).
2. From the crankshaft, the belt goes up and to the left over the A/C Compressor Pulley.
3. From the A/C compressor, the belt continues up and over the Idler Pulley (typically a smooth pulley that guides the belt).
4. The belt then travels down to the Alternator Pulley (usually located high on the engine).
5. From the alternator, it goes down and to the left around the Power Steering Pump Pulley.
6. After the power steering pump, the belt wraps up and over the Water Pump Pulley.
7. Finally, the belt runs down to the Auto-Tensioner Pulley (a spring-loaded pulley that maintains belt tension) before returning to the crankshaft pulley.

For 6.7L Cummins Diesel Engine:

1. Start at the Crankshaft Pulley.
2. From the crankshaft, the belt generally routes up to the A/C Compressor Pulley.
3. It then goes over an Idler Pulley.
4. The belt continues down to the Alternator Pulley.
5. From the alternator, it may wrap around another Idler Pulley (depending on configuration).
6. It then proceeds to the Power Steering Pump Pulley.
7. The belt will then go to the Water Pump Pulley.
8. Finally, it loops around the Auto-Tensioner Pulley before heading back to the crankshaft.

How to Replace the Serpentine Belt

Replacing a serpentine belt on a 2018 Ram 3500 is a manageable DIY task, but it requires patience and the right tools.

Tools Needed:

• Serpentine belt tool or a 3/8-inch breaker bar/ratchet.
• Socket for the tensioner bolt (usually 1/2-inch or 15mm).

Steps:

1. Safety First: Ensure the engine is off and cool. Disconnect the negative terminal of the battery for added safety.
2. Locate the Tensioner: Identify the automatic tensioner pulley. It will have a square hole or a bolt head compatible with your breaker bar or serpentine belt tool.
3. Relieve Tension: Insert your breaker bar or serpentine belt tool into the tensioner's square hole or onto the bolt head. Apply steady pressure in the direction that loosens the belt (this usually involves rotating it counter-clockwise, but verify on your specific engine).
4. Remove Old Belt: While holding the tensioner in the "loose" position, carefully slip the old belt off one of the pulleys (often the smooth idler pulley is easiest).
5. Inspect Pulleys: With the old belt off, take this opportunity to manually spin each pulley (alternator, power steering, A/C compressor, idlers). Listen for any grinding, squeaking, or excessive play. Worn pulleys should be replaced.
6. Route New Belt: Refer to the photograph you took earlier or the text-based routing description above. Begin routing the new belt around all pulleys except the tensioner pulley. Make sure the ribs of the belt sit correctly in the grooves of the ribbed pulleys.
7. Final Tensioner Engagement: Once the belt is around all other pulleys, use your serpentine belt tool or breaker bar to again relieve tension on the auto-tensioner. Slide the new belt over the tensioner pulley.
8. Verify Routing: Slowly release the tensioner. Double-check that the belt is properly seated on all pulleys and that its routing matches your diagram.
9. Start Engine: Reconnect the battery. Start the engine and let it run for a minute or two, observing the belt to ensure it tracks correctly and there are no unusual noises. Briefly turn off the engine and re-check belt seating.

Replacement Interval

Serpentine belts on a 2018 Ram 3500 generally have a long lifespan. Most manufacturers recommend inspection at every oil change and replacement around 60,000 to 100,000 miles, or if signs of wear are observed. However, for vehicles used for heavy towing, hauling, or in dusty/extreme conditions, more frequent inspection and potentially earlier replacement may be prudent. Always consult your owner's manual for the manufacturer's specific recommendations.

Signs of a Failing Belt or Tensioner

Ignoring a failing serpentine belt or tensioner can lead to a breakdown, as many critical engine accessories rely on this belt.

Signs of a Failing Serpentine Belt:

• Squealing or Chirping Noises: Often most noticeable on cold starts or when turning the steering wheel (for power steering).
• Cracks or Fraying: Visible cracks, especially across the ribs, missing chunks, or frayed edges are clear indicators for replacement.
• Glazed or Shiny Appearance: The ribs of the belt may look hardened and shiny, indicating reduced grip.
• Loss of Power to Accessories: Diminished power steering, weak A/C, or a battery not charging properly can indicate the belt is slipping or broken.

Signs of a Failing Automatic Tensioner:

• Squealing/Grinding from Tensioner Pulley: Worn bearings in the tensioner pulley can cause noise.
• Excessive Belt Vibration/Flapping: A weak tensioner spring won't hold the belt taut, leading to vibration.
• Visible Misalignment: The tensioner pulley may appear to be tilted or not in line with other pulleys.
• Belt Slippage: Even with a good belt, a weak tensioner can't apply enough force to prevent slipping.

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