Accessory (Serpentine) belt removal and replacement

[Cdubya]

There is only one belt on the 3.0L ST. If you just replace the belt, it is a far more easy task but I suggest you replace the other wear parts at the same time: belt tensioner (has it's own pulley attached), 2 idler pulleys.

PARTS LIST: (prices at time of writing, Levittown Ford, for my MY2020 ST using VIN#)
L1MZ-8620-F Serpentine Belt $28.79
L1MZ-6A228-B Belt Tensioner $91.45
FL3Z-8678-B lower Idler Pulley $37.76
W713261-S437 Belt Tensioner Screw (2) $2.60
FT4Z-8678-A upper Idler Pulley $25.01

TOOLS:
standard socket set (belt tensioner bolts 10mm, pulley bolts 13mm, belt tensioner release 15mm)
belt tensioner tool set (helpful): https://a.co/d/0AX2NmY

Service manual calls for putting the car on a lift and removing the front undercarriage. Seeing as I did not have a lift, I chose to remove the air intake and do the work from above--it was not easy because of all the piping/hose in the way and have scratched up arms to prove it. It may be easier to do it from below with ramps or jackstands to lift the front end.

Below is the belt diagram for routing the new belt:



TORQUE SPECS:
Timing Belt tensioner bolts: 18 ft lbs.
Upper idler pulley: 18 ft lbs
Lower idler pulley: 35 ft lbs.

See service manual pages attached.

Lastly, TRIPLE check that the belt is sitting nicely on all pulleys before you fire up the engine.

 

[Cruising68]

Nice. I always replace the tensioner and pulleys when doing the belt. Parts don’t last like they used to and on new cars the belt is packed in tight resulting in cuts in your hands


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[Cdubya]

FYI: I had assumed these belts were good for 100k miles, but the owners manual states you just INSPECT at 100k miles and to REPLACE at 150k miles. The condition of the belt I replaced at 95k was very, very good so I guess that makes sense.