2019 Ram 2500 Serpentine Belt Routing, Length & Replacement Guide

As an ASE-certified master technician, I regularly service heavy-duty trucks like the 2019 Ram 2500. Whether your truck is equipped with the workhorse 6.7L Cummins Turbo Diesel or the capable 6.4L Hemi V8, the serpentine belt is the lifeline of your engine's accessories. A snapped belt on a Ram 2500 means an immediate loss of power steering, alternator charging, water pump circulation, and air conditioning.

Below is your complete reference guide for the 2019 Ram 2500 serpentine belt system, focusing primarily on the highly popular 6.7L Cummins single-alternator setup.

Quick answer

Note: The following specifications are for the 2019 Ram 2500 equipped with the 6.7L Cummins Turbo Diesel (Single Alternator). If you have dual alternators or the 6.4L Hemi V8, your part numbers and belt length will differ.

• Belt Length: 126.5 inches
• Rib Count: 8-rib (Heavy Duty)
• OEM Belt PN: Mopar 53041270AA
• Aftermarket Belt Cross-References: Gates K081264HD (Heavy Duty FleetRunner), Continental Elite 4081264, Dayco 5081265
• Auto-Tensioner PN: Mopar 53041267AA (Aftermarket: Gates 38637)
• Idler Pulley PN: Mopar 53041268AA (Aftermarket: Gates 36417)

Belt routing

Pro-tip: Always use your smartphone to photograph the existing belt routing before you remove it. It will save you a massive headache if you get confused during reinstallation.

Because we cannot render an image here, follow this text-based step-by-step description of the routing path for the standard 6.7L Cummins (single alternator):

1. Start by looping the ribbed side of the belt around the bottom of the Crankshaft pulley.
2. Bring the belt straight up, with the smooth side riding against the Water pump pulley.
3. Continue up and route the ribbed side over the top of the upper Idler pulley.
4. Pull the belt across to the passenger side and over the Alternator pulley.
5. Route the belt straight down to wrap around the A/C compressor.
6. Bring the belt across the lower engine block to the driver side, looping around the Power steering pump.
7. Finally, pull the belt up and route the smooth side under the Auto-tensioner pulley before returning to the crankshaft.

How to replace the serpentine belt

Replacing the belt on a Ram 2500 requires a bit of maneuvering, especially on the Cummins due to the massive cooling fan and shroud.

1. Locate the tensioner: On the 6.7L Cummins, the tensioner is located on the lower driver-side front of the engine block.
2. Relieve tension: Insert a 3/8" drive breaker bar (or a dedicated long-reach serpentine belt tool) directly into the square receptacle on the tensioner arm. Rotate the tensioner clockwise (towards the passenger side) to relieve the spring tension.
3. Remove the belt: While holding the tensioner open, slip the belt off the easiest accessible pulley (usually the water pump or A/C compressor). Carefully release the tensioner arm.
4. Thread the new belt: Route the new belt following the path described above, leaving the tensioner for last.
5. Install: Rotate the tensioner again with your breaker bar, slip the belt over the final pulley, and slowly release the tensioner.
6. Inspect: Visually inspect every pulley to ensure the belt ribs are perfectly seated in the pulley grooves. Start the truck and verify smooth operation.

Replacement interval

For the 2019 Ram 2500, I recommend inspecting the serpentine belt every 30,000 miles. As a general rule of thumb, you should replace the belt and tensioner every 60,000 to 90,000 miles. If you use your truck for heavy towing, plowing, or idle extensively (which racks up engine hours rather than miles), lean towards the 60,000-mile mark. Heavy-duty diesel engines create significant torsional vibration that wears out tensioner springs faster than standard gas engines.

Signs of a failing belt or tensioner

Don't wait for your belt to snap while hauling a heavy load. Watch for these common warning signs:

• Squealing or chirping: High-pitched noises, especially on startup or when the A/C kicks on, indicate a slipping belt or a failing tensioner bearing.
• Visible wear: Look for fraying on the belt edges, missing chunks of ribs, or a glazed, shiny appearance on the ribbed side. Note that modern EPDM belts don't crack as noticeably as older neoprene belts; they wear down like tire tread. Use a belt wear gauge if unsure.
• Tensioner bouncing: With the engine running, observe the tensioner arm. A millimeter of movement is normal, but excessive bouncing or chattering means the internal dampener is blown and the unit must be replaced.
• Heavy steering or dimming lights: If the belt is slipping badly, the power steering pump and alternator will underperform.

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