On the 13th-gen F-150 this is one of the easiest jobs on the truck, but access is what decides how long it takes. The 5.0 V8 is the friendliest once you pull the plastic engine cover and the upper fan shroud cover, which gives you a clear shot straight down at the tensioner. The 2.7 and 3.5 EcoBoost bury the tensioner low and behind charge-air piping, so a long flex-head belt tool or a breaker bar with a wobble extension does far more for you than a standard ratchet.
Most people get two things wrong. First, they don't photograph the routing before the belt comes off, then spend 20 minutes guessing which idlers ride on the smooth back side. Second, they don't verify the belt is fully seated in the crankshaft pulley, which you can't see without a mirror and light - a belt one groove off will shred within a couple of miles. While the belt is off, spend two minutes spinning every pulley by hand; a growling tensioner or idler bearing is the usual reason the new belt starts chirping a week later.
| Item | Type | |
|---|---|---|
| Wheel chocks Keeps the truck from rolling while you work at the front of the engine. | Safety | shop |
| Mechanic's gloves Protects hands when reaching between pulleys and sharp aluminum brackets. | Safety | shop |
| Phone camera or paper Photograph or sketch the belt routing before removal; the diagram decal is often missing. | Recommended | shop |
| Socket set, 3/8 in drive 8, 10, 13, 15, 18 mm 6-point Covers shroud, cover and charge-pipe bolts plus the tensioner and idler pulley bolts. | Required | shop |
| Ratchet, 3/8 in drive Long-handle, 10-14 in Main driver for the tensioner and the fasteners in front of the engine. | Required | shop |
| Extension set, 3/8 in drive 3, 6 and 12 in plus wobble extension Reaches the tensioner and lower idler past the fan and radiator support. | Required | shop |
| Serpentine belt tool kit Long 18-24 in flex-head bar with 3/8 in, 1/2 in square drive and 13/14/15/16/18 mm crowfoot sockets Gives the reach and leverage to swing the tensioner where a normal ratchet will not fit. | Required | shop |
| Breaker bar 3/8 in or 1/2 in drive, 18 in Alternative to the belt tool for rotating the tensioner arm on EcoBoost engines. | Recommended | shop |
| Combination wrench 15 mm and 18 mm Fits the tensioner pulley bolt hex when there is no room for a socket. | Recommended | shop |
| Torx driver set T25 / T30 Some engine cover, air box and shroud clips use Torx on these trucks. | Recommended | shop |
| Flat blade screwdriver / trim tool Releases air intake tube clips, push pins and coolant hose retainers. | Recommended | shop |
| Flat blade or nut-driver for hose clamps 7 mm or 8 mm nut driver Loosens the intake/charge pipe worm clamps on EcoBoost engines. | Recommended | shop |
| Torque wrench 3/8 in drive, 10-80 ft-lb Reinstalls the tensioner or idler pulley bolt correctly if you removed one. | Recommended | shop |
| Inspection mirror and flashlight LED Confirms the belt is fully seated in every pulley groove, especially the hidden crank pulley. | Recommended | shop |
| Belt wear gauge For K-section EPDM belts Tells you whether the old belt or a used spare is actually worn out. | Recommended | shop |
| Serpentine belt Correct length for your engine: 2.7 EB, 3.3 V6, 3.5 EB and 5.0 V8 all use different belts; match by VIN The replacement belt itself. | Parts | shop |
| Belt tensioner assembly Engine-specific; check for rough bearing or weak spring Common wear item; replace with the belt if the pulley is noisy or the arm is loose. | Parts | shop |
| Idler pulley Engine-specific Replace if it wheezes, wobbles or the bearing feels gritty by hand. | Parts | shop |
| Brake cleaner or belt dressing-free degreaser Non-residue aerosol Cleans oil or coolant off pulley grooves so the new belt does not slip or chirp. | Consumables | shop |
| Shop rags Wiping pulleys and catching debris. | Consumables | shop |
Tensioner fitting is engine and date dependent: most 5.0 V8 and 3.3/3.5 V6 tensioners take a 15 mm hex on the pulley bolt, some take 18 mm, and several tensioner arms have a 3/8 in square hole for a breaker bar - check yours before buying a tool. Access differs too: the 5.0 needs the engine cover and upper fan shroud cover off (8 and 10 mm), while 2.7 and 3.5 EcoBoost trucks need the air intake tube and sometimes a charge-air pipe or degas bottle bracket loosened (7/8 mm clamps, 10 and 13 mm bolts). Belt length differs for every engine in this generation, so order by VIN.
| Belt tensioner assembly mounting bolt | verify in the service manual |
| Idler pulley bolt | verify in the service manual |
| Fan shroud / upper radiator cover bolts | Hand tight, roughly 7-9 ft-lb (10-12 Nm) - verify in the service manual |
| Charge air / intake tube clamps (EcoBoost) | verify in the service manual |
The 15 mm tensioner hex, 8/10 mm cover bolts and 3/8 in square-drive option cover the great majority of 2015-2020 F-150 engines, but the tensioner fitting varies by engine and production date, so check your tensioner bolt with a 15 mm and an 18 mm before buying a tool, and confirm belt part number and any torque values against the Ford service manual or your VIN.
Most of these engines use a 15 mm hex on the tensioner pulley bolt, with some units taking 18 mm and others providing a 3/8 in square hole for a breaker bar. Check your tensioner with both sizes before buying a tool, and use a long flex-head belt tool on the EcoBoost engines because clearance is tight.
No. On the 5.0 V8 you only need the plastic engine cover and the upper fan shroud/radiator cover off. On the 2.7 and 3.5 EcoBoost you generally only remove the air intake tube and possibly loosen a charge-air pipe or the degas bottle bracket.
It only moves one way off its stop - if it feels solid, you are pushing against the stop. On the 5.0 it typically swings clockwise as viewed from the front of the engine; apply steady pressure and it will release the belt.
Modern EPDM belts don't crack like old rubber ones, they lose rib material, so inspect with a belt wear gauge rather than looking for cracks. Most owners replace around 90,000-120,000 miles, or sooner if there is chirping, glazing, missing chunks or a noisy tensioner.