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2018 Ford F-150 4WD Lariat Sport, SuperCrew, 4WD, 3.5 EcoBoost, Special Edition Package
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Discussion Starter · #1 ·
For a while I've been researching why some 2nd gen 3.5s make a knock-like noise that resembles a diesel. Today I've come across a great video of a 2017 3.5 that sounded identical to a 2018 I filmed last year (I have the video in another thread). This guy mentions that all cam phasers were replaced prior to filming. After a lot of diagnosing, he removes a spark plug and discovers the piston pin is scoring the cylinder wall. Here's a screenshot.


Additionally, in the video's comments section, a Ford technician says this:

"Ford dealership technician here. First off, cam phaser replacement on these Gen-II version 3.5L Ecoboost engines is intended to repair a loud clattering type noise heard, only during cold engine startup and then subsides after about 10 seconds after the engine is started. It was a technical service bulletin which has now superseded to a recall in recent weeks. A piston wrist pin issue like you've pinpointed in your video above, would obviously have that noise present any time the engine is running. What is the mileage on that engine? Good find, by the way."

I assumed this knocking was also caused by the cam phaser issues that plague 2nd gens, but in this example, that's not the case.
Why is scoring occurring? Is there anything that can be done to prevent this from happening?

Here's the full video:
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