Stripped a drain plug on a Cessna 172 last Tuesday

I was doing an oil change on a 172 at our shop in Phoenix when the drain plug just would not torque to spec. It stripped out on me, and I realized the previous guy must have cross-threaded it. I had to helicoil the oil pan right there on the ramp, which took about 45 minutes. Has anyone else had to deal with a helicoil job on a low-time engine where you just know it was someone else's mistake?

2 comments

2 Comments

the_leo1d ago

Been there on a 172 in Tucson last year. Same thing, the drain plug just spun out on me while I was torquing it to spec. The helicoil job is a pain because you have to be real careful not to get metal shavings in the sump. I ended up using a shop vac and a magnet to catch everything, took a full hour. The worst part is knowing some other mechanic rushed through the job and now you're stuck fixing it. Bet the guy who cross-threaded it never even checked the torque after he ran it in.

lilyt901d ago

@the_leo you're right about the metal shavings being the main worry. A little tip though, that shop vac trick works better if you tape a small diameter hose to the nozzle so you can get right up close to where you're drilling. Did that on a Lycoming last month and it saved me a lot of cleanup time. The pan on those 172s is thin too so you gotta be light on the drill pressure.