My 2006 Ford Focus ate its own spark plugs at 78k miles

I bought this car used back in 2019 thinking it would be a cheap commuter. Last month on the highway it started misfiring hard and nearly left me stranded. Turns out Ford designed the cylinder head so the spark plug threads are super shallow and they just strip out over time. My mechanic showed me one plug that literally blew out of the head and took the coil pack with it. Three of four plugs were loose and two had damaged threads. Has anyone else dealt with the whole thread repair kit route or did you just swap the head?

2 comments

2 Comments

rowanc2916d agoTop Commenter

78k miles and the head needs thread repair? That's rough, but I gotta ask - are you sure it's as bad as you're making it sound? Those 2006 Focus engines aren't exactly known for spitting plugs like the old Triton V8s did. Maybe your mechanic is trying to upsell you on a head swap when a simple helicoil kit would do the trick for like fifty bucks. I've seen plenty of these cars hit 150k without a single plug issue, so maybe yours just got a bad batch of threads from the factory or a previous owner overtorqued them. Before you drop big money on a new head, try the cheap fix first. Worst case you're out a few hours of labor and the price of a kit.

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derek_coleman16d ago

yeah i had a buddy with an 04 focus that did the same thing around 90k. helicoil fixed it and he drove it another 40k miles no problem. worth a shot before you go replacing the whole head