The Case of the Missing Oil Filler Cap

It’s possible, the seal, when compressed a bit, may keep some tension on the cap and stop it from loosening. Also without the seal the cap may screw down too far and cause it to skip or strip a thread. But I still like the tether idea. Could drill a small hole in the raised handle of the cap and then fix a wire through it to a spot near the fill neck.

 

I'm sure you will see before you drill a hole but there isn't too much solid material to drill into on that cap handle.

 

Very possible, I may not do anything at all since my cap has always been snug and never came off or been loose.

 

this thread got me to go look at my cap. i had a very hard time getting it off. it was me tightened it a year ago.
i would have gone snug but not to the extent it was. needed channel locks to free it and was nervous about breaking it or filler pipe. so, i guess not a problem with loosening. there was even oil on the seal and neck that i wiped on to prevent sticking last year. more oil, less snugging this year.
the tether sounds like a good idea and there seems to be plenty of room for a small hole in the finger grip of the cap. best use a drill press and small bit sized for chosen wire. i don't see a problem there but the many turns required to snug it down would cause the wire to bind up unless you got fancy with the anchor. Maybe a loose loop around the filler neck.

 

FWIW, My Husky chain-saw does the same thing. I have to get out the channel-locks to loosen it. It has little tooth marks on it from using them. A new cap and o-ring did the same thing. Next time I use it even when it's fully cold, the cap won't budge. It's like someone snuck in and used an impact wrench to tighten it down.

 

lol. every chainsaw i have used has had that problem on gas and bar oil caps. some have a split handle on cap you can wedge the bar nut tool into for cranking on it to loosen...but really a pain sometimes.
correction stihl has flip handles and have not had much problem with it.

 

My cap was super tight. 17x oil changes. Everytime it was tighter than I expected. Sometimes had to get the crescent.
Guys with loose caps, maybe try flipping the oring around.. whatcha got to lose? And report back after next refuel..