Wondered if anyone might know the wrench/socket size for the nuts on the Ignition Coil Bolts on a 2011 Mazda 6. I thought it was 8mm, but it's too large, and 7mm is too small. Trying to change my spark plugs and can't remove those four bolts. Thanks!

 

Technically its suppose to be a 8mm. Looks to be rounded off. I would try a 5/16 socket and see what that does

 

Thanks for the suggestions. I looked very closely at all four nuts and they seemed fine as far as I could tell. I did try the 5/16 wrench and that didn't work. Maybe I need to use a deep socket 8". I was just using a regular box wrench. Thanks again.