Make sure your battery tie down is TIGHT. I was getting that annoying clunking for over a year and finally traced it down to a loose battery tie down. If it’s loose the battery will move around and rub against the frame causing that noise.
So I swapped out my stock suspension w/ some coilovers. And I was really hoping that it would solve the issue if it was because of the front driver's strut. Well, I can confirm it's not because of that (at least for non Si owners). However, I do feel like the sound isn't as loud....but I'll have to see. I still need an alignment, so maybe those guys will find out if something's off in the front that's causing the issue. If not, I may just have to go with @grifocx fix of replacing the transmission mount.
I know I'm not an Si owner, but figured I'd chime in since apparently the transmission mount is the same for the Hatch Sport 6MT and Si's.
I have the same noise that the OP described and posted the video about,except mine may be louder than the video. The sound only occurs when I'm driving over lane markers, road imperfections, etc. According to the dealership, the sound is the brake pad moving within the caliper and is perfectly normal. I was sure to replicate and point out the noise during the drive-along with the mechanic. It was surprising for me how nonchalant the mechanic was about it too. He was basically like "Oh yeah, almost all Hondas do that. It's normal." Pretty hard to accept that this could be normal considering how loud it is but didn't pursue it further with them, However, I made sure that my service record documented that the sound was diagnosed to be normal by the dealership. Next time, I'll go straight to a brake shop to have it checked.
Just wanted to put my 2 cents. Found this forum researching because I had a very similar issue. Rattle/clunk when going over imperfections in the road etc. I have a 2017 Civic Coupe. Took it to the dealer today and they informed me that I have a bad strut that needs replacing (right front). They are changing it tomorrow. All covered under warranty. Hopefully this solves the issue. I just bought the car 2 days ago. Didn't notice the noise on the test drive because the weather sucked and couldn't hear beyond the rain. Car only has 25k miles.
K, I don't wanna jinx myself, but I may have solved the clunking problem on my car. It's only been 1 day, but I hope it lasts. Basically replaced the tranny mount on the left side. The old mount looked fine, seem to have the same "flex" as the new mount. But yeah, no more clunking noise!
I started hearing a clunking noise in my car. I have added eibach prokit springs and was good for awhile. So put the car up on jack stands and tried to move everything around. I found my endlink was loose on the driver side strut. Nut was tight but I was able to move it up and down. I had to get an Allen bit and wrench to hold the endlink still and was able to tighten it more. Gonna drive next weekend and see it if fixed it. Also putting in some 82a Hasport motor mounts to go with my 27won RMM.
I guess I'll throw my hat into this one as well. I don't have a great deal of time to fool with it at the moment... but figure I'll either get into it shortly after Christmas or give it to the dealer overnight to let them look for it (closest one is about an hour away and has only been back the one time for that Freon recharge since I bought the car), along with rechecking my AC which I had recharged last April for a but of noise when the Freon went through the evaporator and also to see if they have newer firmware for the HU. 3 or 4 times I've had it go black after being in reverse and once you're out... it it's locked out until you turn off the car for a bit, long enough for the HU to reset. 2 years... not a great showing for a new-ish car, but not terrible either. Clunks suck. I figured it was end link... sway bar... or engine/trans mount related.
I hadn't thought about brake pads. I figured we had the springs that keep them off the rotor but also kind of hold them in place. Anyone do a pad change on an Si and see? If they don't... I guess they could be flopping all over the place.
the dealer isolated it to the brakes. When I’m on the breaks over imperfections in the road it doesn’t make that noise, but as soon as I take my foot off it’s back. Dealer says there’s nothing they can do. I told them it wasn’t normal and asked if they could replace the brake assembly because of perhaps bad casting, but they have refused. Took it to Honda corporate and they said the noise was tolerable and the noise level was subjective. Refused to fix. So frustrated with Honda over this matter. My commute has some small imperfections in the road the whole way, so I hear the sound the whole way to work and back. Had a TDI golf before this and would much rather have that car back over the headaches with Honda.