2017 Ford F150 3.5 Ecoboost Belt Diagram – Step-By-Step Serpentine
The 2017 Ford F150 with the 3.5L EcoBoost engine utilizes a dual-belt system consisting of a main serpentine belt and a secondary stretch-fit belt for the AC compressor. This guide provides the exact routing paths and professional techniques required to replace both belts safely and efficiently in your driveway or shop.
Maintaining a high-performance truck like the F150 requires a keen eye for detail, especially when it comes to the components that keep your engine cool and your battery charged. If you have noticed a persistent squeal under the hood or visible cracking on your rubber, finding a clear 2017 ford f150 3.5 ecoboost belt diagram is the first step toward a successful repair.
Replacing these belts might seem intimidating due to the tight engine bay of the second-generation EcoBoost, but it is a manageable task for any DIYer with the right tools. In this guide, we will walk through the specific routing for the main drive and the unique challenges of the stretch-fit AC belt.
By the end of this article, you will have the confidence to inspect, remove, and install new belts, ensuring your truck remains reliable whether you are commuting to work or heading out for a weekend of off-roading. Let’s get under the hood and look at the specifics of your serpentine system.
Understanding the 2017 ford f150 3.5 ecoboost belt diagram
The 2017 model year was significant for the F150 as it introduced the second-generation 3.5L EcoBoost engine, which brought changes to the front engine accessory drive (FEAD). When you look at the 2017 ford f150 3.5 ecoboost belt diagram, you will notice that the system is split into two distinct loops that operate independently.
The primary belt, often called the serpentine belt, is responsible for driving the alternator and the water pump. This belt utilizes a spring-loaded mechanical tensioner, which makes removal and installation relatively straightforward as long as you can access the tensioner bolt.
The secondary belt is dedicated solely to the air conditioning compressor. Unlike the main belt, this is a stretch-fit belt, meaning there is no adjustable tensioner or idler pulley to provide slack. This design requires specific techniques or tools to “walk” the belt onto the pulleys without damaging the internal cords.
Identifying the Main Components
Before you begin pulling parts, it is vital to identify the pulleys involved in the main routing. The largest pulley at the bottom center is the crankshaft pulley, which provides the rotational force for the entire system. From there, the belt travels upward to the water pump and the alternator.
The tensioner pulley is located on the passenger side of the engine block. It features a 15mm bolt head that you will use to rotate the tensioner arm, releasing the pressure on the belt. Understanding these locations helps you navigate the engine bay even when visibility is limited by the cooling fans and shrouds.
Lastly, the idler pulley serves as a stationary guide to ensure the belt has maximum wrap around the other components. If you hear a high-pitched metallic grinding sound rather than a rubber squeak, the bearings in this idler pulley are often the primary suspect.
Tools Required for a Smooth Belt Swap
Having the right tools on hand prevents the “half-finished job” headache where your truck is stuck in the garage while you hunt for a specific socket. For the 2017 3.5L EcoBoost, the tool list is relatively short but specific.
- 15mm Long-Reach Wrench: A standard wrench works, but a long-reach serpentine belt tool provides the leverage needed to fight the heavy spring tension of the main tensioner.
- 3/8-inch Drive Ratchet: Useful for removing the plastic under-tray or air intake components to gain better access.
- Stretch Belt Installation Tool: While some pros use a zip-tie trick, a dedicated tool prevents nicks in the belt that can lead to premature failure.
- Small Pry Bar: Helpful for gently guiding the belt over the lips of the pulleys in tight spaces.
- Work Light: The EcoBoost engine bay is deep and dark; a good LED light is essential for verifying the belt is seated in the grooves.
Safety is paramount when working around the front engine accessory drive. Always ensure the engine is completely cool to avoid burns from the radiator or turbocharger piping. Additionally, disconnect the negative battery terminal to ensure the electric cooling fans do not activate while your hands are near the blades.
If you are working on a lifted truck or an off-road build, using a topside creeper or a sturdy step stool will save your back. Reaching over the high grille of a 2017 F150 for an hour can be taxing without proper ergonomic support.
Removing the Main Serpentine Belt
To begin the removal process, you must first clear a path. On the 2017 F150, removing the plastic air intake ducting that sits over the radiator shroud will give you much-needed visibility. This usually requires popping a few plastic push-pins and loosening a couple of hose clamps.
Once you have a clear view, locate the tensioner on the passenger side. Place your 15mm wrench on the tensioner bolt and rotate it clockwise (toward the driver’s side). You will feel significant resistance as you compress the internal spring. Hold the tensioner in this position with one hand while using the other to slide the belt off the uppermost pulley.
Slowly release the tensioner arm back to its resting position. Do not let it snap back, as this can damage the internal stop or crack the aluminum housing. With the tension released, you can now unthread the belt from the water pump, alternator, and crankshaft pulleys.
Inspecting the Pulleys
With the belt removed, this is the perfect time to perform a “health check” on your pulleys. Spin the alternator pulley and the idler pulley by hand. They should spin smoothly and silently. If you feel any grittiness or hear a “dry” rolling sound, the bearings are failing and the pulley should be replaced immediately.
Check the tensioner arm for proper alignment. If the tensioner pulley looks tilted or is not “in plane” with the other pulleys, the internal bushing is likely worn. A misaligned tensioner is a leading cause of belt shredding and “throwing” a belt under high RPMs.
Finally, look at the water pump pulley for any signs of coolant crusting. The 3.5L EcoBoost is known for occasional water pump weeps. If you see orange or yellow crystalline deposits around the pulley shaft, you may want to address the water pump while the belt is already off.
Installing the New Main Belt
When you are ready to install the new part, refer back to your 2017 ford f150 3.5 ecoboost belt diagram. It is often easiest to start by looping the belt around the crankshaft pulley at the bottom and then working your way up. Ensure the “ribbed” side of the belt matches the “ribbed” side of the pulleys.
The smooth side of the belt should only touch smooth pulleys, such as the idler or the back of the tensioner pulley. A common mistake is flipping the belt, which will cause it to jump off the tracks within seconds of the engine starting.
The final step is to compress the tensioner again and slide the belt over the final pulley (usually the alternator or the water pump). Before releasing the tensioner, double-check that the belt is perfectly centered in the V-grooves of every pulley. If the belt is even one “rib” off, it will shred itself instantly upon startup.
The AC Compressor Stretch Belt Procedure
The AC belt on the 2017 3.5L EcoBoost is located behind the main serpentine belt, closer to the engine block. Because it is a stretch-fit design, it can be frustrating for those used to traditional tensioners. You will likely need to access this from underneath the truck after removing the skid plate or splash shield.
To remove the old AC belt, the official manual suggests cutting it if it is being replaced. However, if you need to remove it for other repairs and intend to reuse it, you must “walk” it off the crankshaft pulley by rotating the engine manually with a large socket on the crank bolt while prying the belt outward.
Installing the new stretch belt is where the specialty tool becomes valuable. You place the tool on the crankshaft pulley, hook the belt onto it, and then rotate the engine clockwise. The tool forces the belt to expand and slide over the lip of the pulley into the grooves.
The Professional “Zip-Tie” Method
If you do not have the specialized stretch belt tool, many technicians use heavy-duty zip ties. You cinch the belt tightly to the crank pulley at the 12 o’clock position and then rotate the engine. The zip tie holds the belt in place, forcing it to stretch over the pulley as it turns. Caution: This method carries a risk of the zip tie snapping or the belt being nicked by the plastic edge. If you use this method, ensure the zip tie is rated for high tension and be extremely careful with your finger placement. Never use the starter motor to turn the engine during this process; always use a breaker bar on the crank bolt.
Once the belt is on, rotate the engine two full revolutions by hand. This ensures the belt has “seated” itself naturally. Check the back side of the AC compressor pulley to ensure the belt isn’t hanging off the edge, which could lead to a catastrophic failure during your next highway trip.
Maintenance Intervals and Signs of Failure
Ford generally recommends inspecting the serpentine belts every 15,000 to 30,000 miles, with a full replacement typically occurring around the 100,000-mile mark. However, if you use your F150 for heavy towing, off-roading, or live in an extremely hot climate, you may need to replace them sooner.
Modern EPDM (Ethylene Propylene Diene Monomer) belts do not always crack like the old neoprene belts did. Instead, they lose material from the ribs, much like a tire loses tread. You can use a belt depth gauge to check for “rib wear.” If the grooves are too deep, the belt will slip, even if it looks visually “clean.”
Other signs of failure include glazing (a shiny, burnt appearance on the smooth side) or “chunking,” where small pieces of the ribs have broken off. If you see any fluid contamination—such as oil from a leaking front main seal or coolant from the water pump—the belt must be replaced, as chemicals degrade the rubber compound rapidly.
Why the 2017 Ford F150 3.5 EcoBoost Belt Diagram is Essential
Having the 2017 ford f150 3.5 ecoboost belt diagram saved on your phone or printed in the garage is essential because the routing is not always intuitive. On the 3.5L EcoBoost, the belt makes several sharp turns that can easily be confused, especially when you are working blindly from the top of the engine bay.
If you route the belt incorrectly, the water pump might spin in the wrong direction. This will lead to an immediate overheat condition, potentially warping the cylinder heads on your expensive EcoBoost engine. Always verify the routing against the diagram one last time before you start the truck.
Additionally, the electronic power steering on these trucks puts a unique load on the electrical system. A slipping belt that fails to turn the alternator efficiently can cause “low voltage” codes and weird steering feedback. Keeping your belts in top shape is a direct investment in your truck’s electronic health.
Frequently Asked Questions About 2017 ford f150 3.5 ecoboost belt diagram
How many belts does a 2017 F150 3.5 EcoBoost have?
The 2017 3.5L EcoBoost engine features two belts: one main serpentine belt for the alternator and water pump, and one smaller stretch-fit belt specifically for the AC compressor.
Can I replace the AC belt without removing the main serpentine belt?
No, the main serpentine belt sits in front of the AC belt on the crankshaft pulley. You must remove the main belt first to gain access to the AC compressor belt.
Why is my new belt squealing after installation?
If a new belt squeals, it is usually due to pulley misalignment, a failing tensioner that isn’t providing enough pressure, or fluid (like coolant or oil) on the pulley surfaces. Ensure all pulleys were cleaned with brake cleaner before installation.
Do I need a special tool for the serpentine belt tensioner?
While a 15mm socket and a long breaker bar will work, a dedicated serpentine belt tool is thinner and fits into the narrow gap between the engine and the cooling fans much more easily.
What happens if the main serpentine belt breaks while driving?
If the belt snaps, you will lose your alternator (charging system) and your water pump. The engine will overheat very rapidly, and you should pull over and shut down the engine immediately to prevent permanent damage.
Final Thoughts for the DIY Mechanic
Replacing your belts is one of the most rewarding maintenance tasks you can perform. It requires minimal investment in parts but provides massive peace of mind. By following the 2017 ford f150 3.5 ecoboost belt diagram and taking your time with the tensioner, you ensure your truck remains the reliable workhorse it was designed to be.
Remember to always double-check your work. Start the engine briefly and watch the belt’s path. If it vibrates excessively or makes any unusual noise, shut it down and re-seat the belt. A properly installed belt should run true and silent, even under heavy acceleration.
Stay safe, keep your tools organized, and don’t be afraid to get your hands dirty. Your F150 will thank you with another 100,000 miles of trouble-free performance. Stay safe and keep wrenching!
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