2015 Mercedes-Benz Sprinter Serpentine Belt Routing & Part Numbers

The 2015 Mercedes-Benz Sprinter is a legendary workhorse, renowned for its durability and cargo capacity. However, keeping it on the road requires staying on top of preventative maintenance, particularly the serpentine belt drive system. For this guide, we are focusing on the most common engine configuration in the North American 2015 Sprinter: the 3.0L OM642 V6 Turbo Diesel equipped with Air Conditioning. Note that a 2.1L OM651 4-cylinder diesel was also available, and parts/routing will differ for that engine.

As an ASE-certified master technician, I always recommend replacing the tensioner and idler pulleys at the same time as the belt on these Sprinter vans to prevent premature belt failure down the road.

Quick answer

Here are the essential specifications and part numbers for the 2015 Mercedes-Benz Sprinter 3.0L V6 Turbo Diesel (with A/C):

• Belt length: 80.1 inches (2035 mm)
• Rib count: 8-rib
• OEM belt PN: Mercedes-Benz A0019938996 (or A0019934296)
• Aftermarket belt cross-references: Gates K080801, Dayco 5080801, Continental Elite 4080801 (or 8PK2035)
• Auto-tensioner PN: OEM A6422001370 (Aftermarket: Gates 38407)
• Idler pulley PN: OEM A6422001070 (Note: The OM642 features multiple idler pulleys; verify upper/lower positions when ordering).

Belt routing

Pro Tip: Before removing your old serpentine belt, always take a clear photograph of the existing routing path with your smartphone. Sprinter engine bays can be tight, and having a visual reference makes installation much easier.

For the 3.0L V6 Turbo Diesel, the ribbed side of the belt must engage with ribbed pulleys, while the smooth backside rides against the smooth idler and tensioner pulleys. The general routing path is as follows:

1. Start by looping the belt down around the bottom of the Crankshaft pulley.
2. Route the belt straight up from the crankshaft to the Water pump pulley.
3. From the water pump, bring the belt across to the Power steering pump pulley.
4. Route down from the power steering pump to wrap around the A/C compressor pulley.
5. Bring the belt up from the A/C compressor, over the smooth Idler pulley(s).
6. Wrap the belt around the Alternator pulley at the top of the engine.
7. Finally, pull the slack over the smooth roller of the Auto-tensioner, which sits near the center-left of the engine block.

How to replace the serpentine belt

Working on a Mercedes-Benz Sprinter van often requires navigating a compact front fascia. You may need to remove the upper fan shroud or the air intake tubing to gain adequate clearance to the front of the engine.

1. Locate the tensioner: Find the spring-loaded automatic belt tensioner on the front of the engine block.
2. Release the tension: Use a long-handled serpentine belt tool or a breaker bar with the appropriate E-Torx (female Torx) socket to rotate the tensioner. Rotate the tensioner counter-clockwise (or in the direction that compresses the internal spring) to release the tension on the belt.
3. Remove the old belt: While holding the tensioner open, slip the belt off the easiest accessible pulley (usually the alternator or upper idler). Carefully release the tensioner back to its resting position.
4. Route the new belt: Follow your reference photo and the routing steps above to snake the new belt around all pulleys except the final one (leave the alternator or a smooth idler for last).
5. Install the new belt: Compress the tensioner again, slip the belt onto the final pulley, and slowly release the tensioner.
6. Verify alignment: Double-check every pulley to ensure the belt ribs are perfectly seated in the pulley grooves. Start the engine and observe the belt for any wobbling or chirping.

Replacement interval

For the 2015 Mercedes-Benz Sprinter, the serpentine belt, tensioner, and idler pulleys should typically be replaced every 60,000 to 80,000 miles. Because Sprinters are frequently used for heavy towing, delivery routes, and extended idling, the drive accessories experience higher wear than a typical passenger vehicle.

Signs of a failing belt or tensioner

Do not ignore the warning signs of a failing accessory drive system, as a snapped belt will immediately disable your alternator, water pump, and power steering. Look and listen for:

• Squealing or chirping noises: Especially noticeable on startup or when the A/C compressor engages. This indicates belt slip or a weak tensioner spring.
• Visible belt wear: Check for deep cracks, missing chunks of ribs, or a frayed shiny appearance on the smooth side.
• Tensioner bouncing: With the engine running, watch the auto-tensioner. If the arm is jumping or vibrating excessively, the internal dampener has failed.
• Bearing noise: A low grinding or howling sound from the front of the engine usually indicates a failing bearing in an idler pulley or the tensioner.
• Heavy steering or battery warning lights: If the belt is slipping badly, the power steering will feel heavy, and the alternator won't charge the battery properly.

If you aren't comfortable tackling this repair on your own or lack the necessary E-Torx tools, don't risk leaving your van stranded. Find a trusted shop on Repairius.