I posted earlier at 500 miles that i didn't have any rattles but at 3500 miles I am taking my car in to the dealer for a very loud rattle in the front dashboard close to the NAV screen. Ive tried everything to isolate it but cannot. Its very loud like the whole dashboard is flexing. Im pretty dissapointed - none of my Jeep's, BMW's or Mercedes' had rattling dashboards - they did have other problems though.

 

The day my car drove off the lot it sounded like someone had marbles in a shoebox and shaking it while driving over rough pavement, on that passenger A-pillar area.
It almost sounded like a blown speaker buzz at times. LOUD

The dealer repaired it under warranty by removing the top dash panel and putting foam tape underneath.

2 months later it began rattling again but not so bad.
They repaired it again under warranty.

About a year later the lower panel that covers the front passenger seatbelt began rattling right where the seatbelt runs in/out of it. Not very loud but still occasionally rattles over rough pavement.

About the same time the dash began rattling again so they reparied it again by sticking more foamy tape.
Immediately afterward I noticed the other side...the driver side A-Pillar area began rattling on rough pavement, as well as a new low-level occasional rattle somewhere under and behind the instrument panel.

At this point I guessed they were'nt able to eliminate the rattles...and figured that top panel had been fussed with too many times for any good.

Now out of warranty I'll live with the occasional rattle.
It's not like I'm driving what seems like a bucket of bolts or anything, still is pretty tight. Just an occasional noise.

Yes, it was a very common trouble with the 03-05 Civic models.

 

My old HCHII did not have a rattle in the dash, but the backseat, panel under the steering column and side panels rattled a lot. The replacement HCHII I just got has a rattle in the dash by the driver side window defrost. There is a rattle on the passenger side, but I can not been able to narrow down exactly where it is coming from.

 

I haven't had any problems with it so far. But, it is less than a month old and only 900 miles.

 

I thought mine had a couple of dash rattles, but each time I investigate, the cause is something I can't blame on Honda... keys rattling, something in the center console storage bin rattling, etc. Be sure to remove that stuff (and try just a single key instead of a big key ring) when trying to investigate suspect rattles.

The keys were a surprise to me. I never had rattles in my old car with the same key ring. I'd swear the HCHII rattle noise was from inside the dash... didn't sound anything like keys... but when I put my hand on the keys, the rattle immediately goes away! I guess I need to get those rubber / plastic key holder thingies to stop my rattling!

 

I have found that recently my car has been a lot noisier, and it was fairly noisy before. Part of this is due to the fact that my recent tire change has moved me to a brand that is noisier when overpressured compared to my old OEM ones. However, I have made my whole vehicle quieter by buying a few rolls of self-adhesive duct insulation, and coating some of the sheet metal on the car to reduce vibration. This is the same idea as dynamat, but more than 5 times cheaper, with almost no added weight. So far I've layered the hood, the trunk, the trunk lid, plastic panels under the steering column, door pockets, and the license plates (easiest places to access).

Eventually I will probably coat a few spots behind the bumpers, the doors, and the ventilation ducts (I figure it can't hurt to use duct insulation on ducts...).

Opening and Closing either the trunk or the hood before used to have a cheap metallic sound. Now it sounds more like closing a wooden chest (no vibration, more solid feel). Clarity from my rear speakers has improved substantially. I figure matting the doors should do the same for the front speakers. Engine noise is reduced. I'm satisified with the improvement for the price.

 

I knew the answer to the rattle making me insane would be here. Thanks! I know what I'll be doing this weekend - assuming I don't lose my mind before then.