2018 Ford Transit Serpentine Belt Replacement Guide

The serpentine belt on your 2018 Ford Transit is a critical component, responsible for powering everything from the alternator and water pump to the A/C compressor and power steering pump. This guide will walk you through the essential part numbers, routing, and replacement procedures for your Transit.

Note on Engine Variations: The 2018 Ford Transit was available with three primary engine options: the 3.7L V6, the 3.5L EcoBoost V6, and the 3.2L I5 Power Stroke Diesel. Belt lengths, part numbers, and routing can vary between these engines. Always verify part numbers with your vehicle's VIN at your local dealer or parts supplier before ordering.

Quick Answer: Belt & Component Part Numbers

Below are common part numbers for the 2018 Ford Transit. These are for reference only and should be confirmed against your specific vehicle.

For 3.7L V6 & 3.5L EcoBoost V6 Engines

• Serpentine Belt Rib Count: 6-Rib
• OEM Belt Part Number: Ford JK6-954-A, Motorcraft JK6-954
• Common Aftermarket Belts: Gates K060948, Dayco 5060948, Continental 4060948
• Belt Tensioner Assembly: Ford F2GZ-6B209-A, Motorcraft BT-131
• Idler Pulley: Ford 9L3Z-8678-B, Motorcraft YS-370

For 3.2L I5 Diesel Engine

• Serpentine Belt Rib Count: 8-Rib
• OEM Belt Part Number: Ford BK2Q-6C301-BA, Motorcraft JK8-723-A
• Common Aftermarket Belts: Gates K080715, Dayco 5080715, Continental 4080715
• Belt Tensioner Assembly: Ford BK3Z-6B209-A, Motorcraft BT-119
• Idler Pulley: Ford BK2Z-8678-A, Motorcraft YS-381

Belt Routing

Properly routing the serpentine belt is crucial for the function and longevity of the components it drives. An incorrectly routed belt can cause components to spin backward, slip, or fail to operate, and can cause the belt itself to shred or fly off.

Before you do anything, take a clear photograph of the current belt routing from a couple of angles. You can also find a belt routing diagram on a sticker under the hood in the engine bay.

While the exact path can vary slightly based on options, a common routing for the V6 engines is as follows:

1. The belt starts by wrapping around the main crankshaft pulley at the bottom.
2. From the crank, it moves up to the A/C compressor.
3. Next, it goes around the smooth side of the uppermost idler pulley.
4. It then wraps around the alternator.
5. From the alternator, it routes to the power steering pump.
6. It continues to the water pump.
7. Finally, it wraps around the belt tensioner before returning to the crank pulley, completing the loop.

The belt should be routed with the ribbed side making contact with all grooved pulleys (crank, A/C, alternator, etc.) and the smooth, flat side of the belt making contact with any smooth idler or tensioner pulleys.

How to Replace the Serpentine Belt

Replacing the belt is a straightforward job for a DIYer with the right tool. The main challenge is accessing the belt tensioner, which is under spring load.

Tool Required: You will need a serpentine belt tool, which is a long, thin ratchet with various socket and crowfoot attachments. Alternatively, a long 3/8" drive breaker bar can often fit into the square hole on the body of the tensioner.

1. Locate the Tensioner: Find the automatic belt tensioner. It's an assembly with a pulley mounted on a spring-loaded arm.
2. Release Tension: Fit your breaker bar or serpentine belt tool into the square hole on the tensioner body. Rotate the tensioner against its spring pressure. This will loosen the belt, allowing you to slip it off one of the pulleys (the topmost, smoothest pulley is often the easiest).
3. Remove the Old Belt: Carefully unthread the old belt from all the pulleys.
4. Install the New Belt: Using your photo or diagram as a guide, carefully route the new belt around all pulleys except for one (again, the top idler is a good choice for the last one). Make sure the ribs are correctly seated in each grooved pulley.
5. Apply Tension: Using your tool, rotate the tensioner again and carefully slip the belt over the final pulley. Once the belt is in place, slowly release the pressure on the tensioner, allowing it to apply tension to the new belt.
6. Final Check: Double-check that the belt is correctly seated in every pulley and that the routing matches your diagram or photo perfectly. Start the engine for a few seconds to ensure everything runs smoothly and quietly.

Replacement Interval

Ford generally recommends inspecting the serpentine belt at regular service intervals and replacing it when it shows signs of wear, or as a preventative measure around 100,000 miles. However, belts can fail sooner, especially in harsh climates. If the belt tensioner or an idler pulley is being replaced, it is always best practice to install a new belt at the same time.

Signs of a Failing Belt or Tensioner

Be aware of the following symptoms that indicate it's time for a replacement:

• Squealing or Chirping Noises: This is the classic sign of a slipping, worn, or contaminated belt.
• Visible Wear: Inspect the belt for cracks, fraying, glazing (shiny, smooth spots), or missing ribs.
• Grinding or Rumbling Noise: This often points to a failing bearing in the tensioner or an idler pulley.
• Tensioner Pulley Misalignment: Look at the tensioner while the engine is running. If the pulley is wobbling, bouncing excessively, or appears crooked, the tensioner assembly is likely worn out.
• Accessory Malfunctions: If your battery isn't charging (alternator), the A/C isn't cold (A/C compressor), or steering becomes difficult (power steering), a failed belt could be the cause.

By following this guide, you can ensure the serpentine belt system on your 2018 Ford Transit remains in top condition.

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