Helicoil for oil filter cover - what size is the bolt?

You need to verify the pitch of the threads before you buy the kit. I think you are in luck that M6 only comes in 1.0 thread pitch...but make sure to check to be safe. M6 means the diameter is 6mm thread but the number after that is the pitch (# of threads per mm)..in this case 1.0 threads per mm. The X 16 is definitely the length of the threads in mm but that doesn't matter when purchasing a helicoil. They make thread pitch gauges so you can 100% verify the correct pitch. Or you can go in the fastener section of Home Depot or Lowes...they will have bolts and holes setup so you can screw in the bolt you are curious about to verify the correct thread size and pitch.

Thanks Codeman. Hadn't thought about the pitch. I'll double check that before I grab the kit. Anybody know if home depot or lowes sells the heli-coil kits?

Thanks again.


You'd be better off finding helicoils at an autoparts store or at Sears. Or better yet, ebay if you have some time to wait for shipping.

My dad just did my friends lower oil filter bolt also. Drilled it out tapped it then put the heli coil in. I'm pretty sure we used an m8 heli coil tap along with the m8 heli coil. I think...

Whew - fixed it. It is, in fact, a standard M6 (1.0 pitch) 16mm bolt. I used a "Fix-a-thread" M6x1(inch) kit that is identical to the heli-coil system. Found it at autozone on my way home from work for $29. Only took about 30 mins and the bolt feels much more solid and secure than it ever did before. The fix-a-thread comes with a nifty little tool that triples as a tap wrench, coil inserter, and punch to remove the tang.

Thanks for the help!


PS - Just saw rayztruckz307 reply. The bolt has an 8mm head, but the threaded part is 6mm, so that's probably what you were thinking.

Yea maybe I'll have to go look for the tap now

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