Last Thursday was one of the worst days I've had in a shop

Had a 2015 Ford Explorer come in with a weird misfire on cylinder 3. Swapped plugs and coils, still had the issue. Turns out it was a cracked valve seat after I wasted 6 hours and the customer was standing there watching me the whole time. Has anyone else dealt with those 3.5L EcoBoost motors acting up like that?

2 comments

2 Comments

the_xena14d agoMost Upvoted

Ah man, that's rough. I've seen those 3.5s do some weird stuff. Had a buddy's F-150 with the same motor, same exact problem - misfire on cylinder 3 that just would not go away after all the usual parts swapping. Turned out to be a hairline crack in the exhaust valve, not the seat, but close enough. The whole situation makes you feel like an idiot when the customer is just standing there watching you chase your tail. Those engines are great for power but man, they've got some heat-related issues that pop up.

faithwalker14d ago

Man @the_xena those exhaust valves get scary when they're thin!