I always thought a loose spark plug was no big deal until last Tuesday

I was working on a 2015 F-150 in my home shop, just doing a basic tune-up. I pulled the first plug and it came out way too easy, like it was only finger tight. The threads were stripped and the cylinder head was damaged. I had to pull the head, tap new threads, and install a helicoil kit. It took me six hours and cost the customer an extra $300. Anyone else had a simple job turn into a nightmare because of a previous mechanic's mistake?

3 comments

3 Comments

the_oscar21d ago

My old shop had a torque wrench just for spark plugs after a similar mess. The spec for those Ford Triton engines is only 14 foot pounds. People crank them down like lug nuts. You gotta chase the threads with a tap before you even try to install a new plug now. Saves a huge headache later. That helicoil job is a real pain, especially on the back cylinders.

jones.kim20d ago

Ever try a thread chaser instead of a tap?

sean4820d ago

Man, 14 foot pounds feels like nothing, right? I always tell guys to put a little anti-seize on the threads too, it helps a ton. That tap trick is solid gold, saves you from having to pull the head when a plug strips on the way in. The worst is when someone else's hack job leaves those aluminum threads just hanging on by a prayer.