This is a post to bimmerforums.com explaining what I have done to stop my E36 323is (1998) from driving me crazy with rattles because of my bass.
Post starts below this line.
Revised: June 18, 2008
Caution: language, and I don't care about censoring myself. If you are offended, please lighten up or ignore my post.
I've got a 15" Tumult, it's kinda loud, it's no LMS Ultra... but it's enough to suck down 1200W with flying colors and make every interior panel of my car flap and rattle. I can't stand rattles, but I love immaculate bass that can kick you in the chest. It's like a never-ending power struggle, the louder the bass, the louder the rattles become and more start to show up. Without rattles, there's nothing to distract you from the music, or the feeling of it. Over the years, I've fixed almost all of the rattles in this damn thing (at least all of the major ones that would bug most people), and I only really used two main ingredients to do it:
Polyfill: You'll probably want about 3-5 lbs of this fluffy stuff. This is the stuff you'd stuff pillows and duvets with. You can get it at arts & crafts supply stores, like Hobby Lobby or something. I think some wal-marts carry it. You stuff it behind panels so that it constantly applies a force to them, and usually increases the distance between panels just slightly. Save for gluing everything down, this is the cheapest, and most effective option for stopping panels from rattling against each other. Things will still be flapping, yet not as much, and at least they aren’t rattling against each other! I've used about 8-10 lbs of the stuff so far
Deadener: Aka: Dynamat, etc. Sound deadener lowers a panels (usually *metal panels*) resonant frequency by adding mass, and helps absorb mechanical vibrations (converting it into heat [we are talking micro to miliwatts a yard here...]) - it can also be used to help tie pieces together since it's a thick and viscous material. Deadener is really good at absorbing lots of the high frequency harmonics that are created when things rattle against metal. (EG: turning a higher pitched 'tap tap' of a knuckle, to a lower and much more muffled 'thud thud') Check out Second Skin Audio, inexpensive, great stuff. I've searched around for lots of comparisons between deadeners, and price for quality, in my opinion, is perfect with these guys. You don’t want asphalt deadener! It eventually will liquefy and is impossible to remove after about a year. Plus, asphalt reeks almost indefinitely. Google for asphalt deadener nightmares in warm climates in the summer... Yah, Gross. (SSA is all butyl, dynamat is butyl+asphalt mix, dynamat extreme is all butyl -and stupid expensive)
More about deadener: You don't need to do your entire car if you are just after rattles. I really didn't want to add weight to my car, I like it's sporty feel (though my front struts are shot...) The E36's already have a good deal of deadening material already installed, some directly applied to the floor pans and transmission tunnel on the body, and other kinds via foam insulation behind panels all over the place. The car's pretty quiet, but almost every compressed pulp panel inside the car flaps like clothes on a clothesline with decent bass. The trunk is another matter, for crazy loud bass, you really DO need it on the trunk deck lid. If you can't justify spending the money on deadener, at least bring yourself to score at least one sheet (usually a square yard), and concentrate all of that around where the lock is (explained below), and you'll be waaaay better than if you had none at all. That lock is obnoxious, and is a HUGE contributor to rattles inside, and especially so outside.
Bad boy bass and driving performance don't quite go hand in hand. Subs are heavy, deadener is heavy, cheap batteries are heavy, amps suck down power like nothing else, etc. It's all a compromise.
For low to moderate bass that does not make your windows flap, you probably just need some polyfill so you can skimp on the deadener. Really, the rear windscreen deck lid, trunk lock, sunroof, and rear seat latches are really of your primary concern. Fix the ones that seem most annoying and loudest to you, and move on from there to the next loudest thing that rattles. For insane bass that seems to rattle everything, you need both polyfill and deadener... and a good deal of time on your hands.
Major culprits that I have had to address so far: (in no particular order)
-Sunroof control panel
-Door cards & pockets/cubby holes (front and back)
-B-pillar trim & seatbelt adjusters
-Fold-down seat latches
-Rear vent windows (2door coupe)
-Rear deck (inside, under rear windscreen)
-Trunk lock/latch & moving parts
-Taillight covers (inside)
-Trunk carpeting (sides and the floor)
-Misc. trunk paneling (plastic subfloor, etc)
-Rear license plate
-Rear license plate light trim
-Anything NOT tied down or stiffly secured to something - so any garbage or shit you have in your car, stuff in ashtrays, loose change in cup holders, etc.
Other things that make noise that I haven’t bothered to fix yet (I'm so tired of fixing these things...):
-Trunk Vent Flaps
-Rear bumper (most likely due to rear trunk vent flaps)
-Things in the trunk I can't track down
Here's what I have done so far, in detail, to REALLY quiet down my car:
Sunroof: The only thing that really worked for me was to shim it. My souvenir, grade 8 LCAB bolt head, with an inch of thread that I snapped off, shimmed in-between the sunroof and that surround gasket- and a folded up, empty Orbit Gum pack worked perfectly. Yes, that's GHETTO as hell, and I bet you are wondering what other genius ideas I have for the rest of the car... (bear with me on this one) But, except for taking the sunroof apart and gluing everything that doesn’t move together, and somehow stiffening all of the mechanisms without binding them up, there isn't much else of an option.... You just have to shim the shit out of it and deal with re-inserting the shims when they fall out, if you open the sunroof. Plus, working on the sunroof sucks, it's messy and greasy. Deal with that how you wish.
Sunroof control panel: Pop this cover off (where the motor for the sunroof is) and stuff that with polyfill. This doesn't rattle much all on its own, but it's right next to your face so it's REALLY noticeable when it does
Center console: Take it apart, remove any of the broken pieces of cup holder arms (or re-glue them), and shim some of the joints that make up that really creaky piece of crap. If you don't care about the modular organization of the center console, you may want to glue some modules down, to make it all one unit. You can also use strips of deadener to sort-of tie the modules together, and reduce the squeaking when you lean on it. I've installed a hardwired phone charger to my ignition, where the wire comes out near my handbrake. So, the shimming action this wire comes out under the center console torques it and stiffens up the whole thing for me, so I didn't need to do much to it. Clean out all the garbage and loose change - it really does make a racket and it's hard to tell where the noise is coming from. If the cup holder bend-y arms have broken off, you can glue them back at the bottom of the cup holder, and then use a stiff, thick rubber band around the outside of the cup holder (you won’t see it from the cabin) to reduce the strain of the glue joint. I had some Loctite Prism 480 leftover from a speaker recone, which is super glue on crack and PCP, so that did wonders for fixing the cracked joints underneath.
Front Doors: Unclip them, stuff some polyfill back there, re-glue both of the door pockets to the panel (they most likely came off the door card when you pulled the door panel off), and glue together ALL parts that have come undone, or need a little re-enforcing on the door panel. After almost 10 years, my door cards were falling apart. The black plastic re-enforcement strips where the clips mount were almost completely torn off, and needed some 'Loctite Super 77' spray adhesive lovin'. You can get that at home depot or Lowes in the glue section. That stuff, after you let it dry overnight or a day or two, got quite stiff-those suckers are never coming back off. I found this article that has pictures of what I'm talking about, this guy used RTV - any good glue will do. http://www.bmwe36blog.com/2007/03/28...36-door-panel/ (mirror with larger pics) Some deadener on the door pocket plastic isn't a bad idea if you have enough to spare. Anything that is put in those plastic pockets may rattle around, and the plastic pocket will greatly amplify the rattles unless it's damped with deadener. Deadener elsewhere on the card is a good idea, but I don't think it needs it if you do the polyfill right, and the foam/plastic splashguards on the door are still intact. Replace any broken door panel clips (#51 41 1 973 500). Now would be a GREAT time to replace your window track slides so you don't have to do it down the road when they fail and the glass drops into your door, or the grease hardens and making the regulator think the window is stuck. (#51 32 1 938 884, 2 per door) Clean those tracks the clips slide on very well, get all that hard grease out, and then re-lube with white lithium grease. Try not to spray it onto the window! And DEFINATELY don't roll the window up/down so overspray rubs against the window lip felt! It takes FOREVER to clean back off!
Rear Doors: (I have a coupe, so I don’t have these) I would assume these will be quieted down (if they rattle) with some polyfill stuffing behind them. Any other rattles associated with the 4 door chassis rear doors, you are on your own.
Front Seatbelt Adjusters & B-Pillar Paneling: Take off the little darth vedar/weird-penis-head-looking caps over the bolts that hold the adjusters on, put some deader on these so it's firmly attached, and moderately difficult to re-attach. Pull off the panel that covers the pillar that the seat belts are on, and stuff some polyfill in there too. I did not unbolt the adjuster for this, just put it in its lowest position, and pull the top of the panel off. Try not to get too much near the belt or close to the belt winder at the bottom. I don't think it will be a big deal, but I sure don't want to have to take everything apart to get at the seatbelt reel, just to clean out polyfill, or replace it if it gets jammed. I had to go back and add even more poly to my driver’s side panel.
Rear passenger armrest/side panels: (2 door coupe) Stuff with polyfill. These panels just pull off. Remove the rear seat bolsters, and grab one of the sides and pull. Evenly disperse polyfill in there, and put the panel back in its place. Try not to have too much in there, or the panels will just pop back off and will be annoying and difficult to get to stay in place. It's held in with the felt, curved lip, trim stuff. There are no clips, so too much polyfill will just make the panel fall off. Use a small flathead to get the trim lip back over the panel.
Rear passenger Windows: (2 door coupe) For me, these flex a lot and rattle against the rubber seal. Yes, they move enough completely unseal and chuff air. I was kind of surprised, and you wouldn't think the windows would be causing noise, but run some test tones, listen around, and put pressure on the rear windows and you'll see that they do indeed make some noise if your bass is loud enough. As far as I can tell, the clamp/latch is not adjustable, so the only way to stop the window from flexing is to add mass to it (which you can't really do because it's glass) or shim the shit out of the gasketing, like I did for the sunroof. Earplugs, cut in half, work OK for this. Get an economy bottle of them for 5$ or so. (If you are bothered by flapping glass, YOU SHOULD already have and be using some of these!!) Stuff 4-8 halves under the rubber seal lip on the top and bottom about midway between the sides of the window. You can see the earplugs from the top, when you go to the door to get in the car. So take a sharpee and black them out - nobody will notice. This is not the best solution, and wound up kind-of sucking. You can't really open the window much, as the bottom ones will just fall out. If this is not enough to stop the flapping, you need to roll up some 1 - 1.5" wide strips of deadening material such that the material is outside, and the foil backing is inside. Then insert them as gasketing, into the gasketing. I wound up having to do this, and if you have the deadener, it's best to just start with that. It's a good idea to clean out any debris in the gasketing, the deadener will stick better and won't fall out or anything. As of right now, I need to go back and add more to one side. It's really difficult to get enough tension against the window since you need to use about 1/4", 3/8", or even 1/2" wide strips to apply enough pressure.
Rear Deck: This is a F$*$^ing monster. Polyfill is your absolute best friend here. The deck will flap up and down and rattle against anything that's holding it in its place, or within an inch of it. The whole concept of removing rattles is to stop separate parts from flapping against each other, and this bastard can be a challenge. It's SO light, and SO big, it's like a kite in wind. The only solution that I have found that makes it shut the F$&# up besides removing it, is to stuff the deck silly with polyfill. The card is held down by two tabs at the very back under the rear windscreen, by the middle brake light housing, by the C pillar paneling, and by the rear seats and the long black plastic piece that's plastic-riveted in place. I had removed the plastic piece years ago when doing a headrests delete for better visibility, and never bothered to put it back in (so I don't know if this part has vibration issues, if it does, pieces of deadener, evenly spaced, should be sufficient - or just remove it like I did). So if you want to remove the deck for some reason, keep in mind that it's a pain to get those tabs back in their spots, and wedge this thing back under the C pillar panels and wrestle the thing into place. In my case, I've had to stuff the deck so much to keep it from flapping, that the back portion of the deck has bowed up, and is now touching up against the rear windscreen. - That's a good inch or so, it may look funny if your interior is otherwise pristine looking. However, it's MUCH quieter now. The way you stuff it is mainly from underneath behind the rear seats. Fold the seats down and look, there are 4 rectangular holes under the deck - stuff from there. You may need to undo that long black plastic piece, under the seat latches, and lift up the deck with a screwdriver, (as per my headrest delete DIY) and stuff from there too. Other than expanding foam or spraying lots of adhesive up there to simply glue the damn thing down - you don't have much else of an option. The deck will STILL vibrate and flap around, I don't think you can stop that, but what you can prevent is stopping it from flapping against anything
Rear center brake light: This isn't much of a problem if you stuffed the hell out of the rear deck, but you *may* want to pop off that plastic grille and try stuffing some polyfill in there too. It may help a little bit, or it may not do shit for you. You may need to shim this against the rear windscreen with something, If it's a problem, use your imagination. Someone here had success in shimming the whole deck where the rear brake light is against the rear windscreen (with cut up cardboard starbucks coffee cup hand protector things, none the less), but with really really loud bass, just shimming the center brake probably will not be enough to stop the deck from flapping at all.
Rear seats: I always have one down when I'm running bass. Two reasons: 1) I can't hear if the amp is clipping and I should turn it down so I don't bake the coils, and 2) it kills the bass from entering the cabin. I don't want to start cutting holes to vent the trunk, so I just deal with it. The trunk is rather sealed off - I assume the engineers did that on purpose so that didn't have to load up the trunk with all sorts of deadening material, instead, the rear seats will just isolate the road noise that leaks into the trunk. Either way, open or closed, the seat latches rattle. This is one of the last things I fixed, because after I deadened the rest of my car's interior, I could turn up the bass without hurting my ears from all of the high frequency rattling... Since I run it louder, the latches - even when not shut - would now rattle big-time. I have a solution for this, but it's not really that great. What I did was jamming some deadener in the latch mechanism and on the sides of the latch hook. The latch is very loose in construction, so the parts just sort-of wobble around in there. A lot of people have complained that the whole seats themselves are rattling, but from what I've experienced, it's really only the latches, or other parts in the trunk. My rear seats are pretty damn dead- except for the latches. Someone stuffed a bunch of polyfill into the latches, and that apparently worked fine for him - so if sticking deadener material and foil backing into the latches it's a big problem for you, you may want to try that. Other than that there's really no other solution except to either remove the seats, or disassemble the latches and somehow stiffen them up. That's going to take a lot of time. I've had no problems with the deadener in the latch, however I do need to manually actuate the handle to the return position to shut the seats, otherwise they won't latch. I did not have to do this before.
Trunk: This will also take some time, especially if you run bass with the rear seats down to allow it to enter the passenger cabin. I've spent days on this & the parts around it. I wound up deadening the spare tire well, under the plastic flooring shelves on the left, the frame crumple-post near the battery and plastic panel above it, and the long thick black plastic trim on the bottom of the trunk opening. (Deadening the spare tire well was not necessary to fix rattles, but reduced the road noise because I ride with one of my seats down.) I added copious amounts of deadener to where the plastic shelves rest on the car body, and where they bolt down. Brake light covers will need some polyfill lovin, some deadener to those can't hurt, if you can spare the cost, (otherwise a buttload of poly will be fine for those). I don't know how hot it gets near those lights, I'm sure the bulbs are hot enough to give you a 1st degree burn, after they've been on for a long time (brake light bulbs especially)... So that is something to consider and test for yourself. Polyfill does burn, and since it's a very fine, fibrous material - it will burn fast once ignited. Behind the carpeting panels, stuff some polyfill in those, the carpeting will flap and rattle against body of the car. Wire looms in the back may rattle some too (especially when driving over bumps). The long black plastic trim piece, in the very back, with a hole in the center to allow the trunk lock to secure to the lock post - that thing, I took it off and added a ton of deadener to that (but in doing so, destroyed the plastic rivet clips and have not found replacements outside of the dealer -so that trim panel is just sitting there in my car...). That whole piece rattled, & it's almost as wide as the car. I added some small strips of deadener to the sides of the lock post - the rubbery ones that look like a V, this stiffened up the lock up just a bit. If you have a CD changer, try not to store loose CD's in that cubby hole, they can make a racket too. Make sure the bolts are tightened for that as well.
Rattling items for the outside of the car that are also audible from inside the passenger cabin:
On the outside of the car, you've got mainly the trunk lock, the whole trunk lid and shocks, your license plate (use all 4 screws, deaden the plate if you can, & make sure the plate isn't rattling against your car's paint!) the rear bumper (particularly the sides that meet the wheels, where those flappy vents are), exhaust heat shield, and maybe where window seals are leaking and letting air chuff though. Not much else rattles on the outside of the car.
Trunk Lid: Take off the carpet & toolbox, and add as much deadener to it as you can afford!!! 2 layers is good, 3 is better - especially behind the panel with the license plate. It's a pain in the ass, but the more you can cram in there, the better. To stop resonances and panel flex, place deadener in the center of large panels. Deadener on edges of metal does not help too much. Try to put pieces of deadener on all of the joints were metal is welded or touching together - this will help make the trunk lid REALLY all one piece. Since it's really just spot-welded together, the sheets of metal that are not welded can vibrate together - and I think that's what makes most cheaper passenger cars with bass rattle SOOOO horribly. The trunk lid shakes and flexes like a monster. The stiffer you can make it, the bass will be louder, more contained, and your car will emanate rattles less to the outside (and inside). Your bass will be louder if you stiffen it up because the bass will be more efficiently directed towards the passenger cabin, instead of the majority of it transmitting through the flexing trunk panel, to outside where it is wasted and obnoxious. After you've put on a ton of deadener, stuff the holes tightly with polyfill. You can cram I think about 2-3, maybe 4 lbs of the stuff in there. If there are any rattles that aren’t deadened, the thick polyfill will help absorb the emitted sound that is emitted into the air of the trunk lid, and thusly into the passenger cabin. I also undid the gas shocks for the trunk (they just unclip with pliers), stuck some deadener on the nubs, and reattached the shocks. The trunk closes and opens only slightly stiffer, but the whole thing feels much tighter in tolerances, smoother, and less loose and wobbly - the way it should be. Someone has also suggested that you take the trunk lid carpet and toolbox off, temporarily cover up all the holes with plastic, and fill the trunk lid with expanding foam, let dry, then re-assemble the paneling. This would be great, but it is messy and fairly permanent. You have to be careful not to get the foam all over and surrounding the locking mechanism, otherwise your lock won’t have any room to function anymore. Most likely this is a much better solution than polyfill, I probably would have done this if I thought about it, but what I have now is good enough for me & I'm too lazy to remove all the polyfill and basically start over with the lid (except for the deadener, you definitely need some of that no matter what you do.)
Trunk Locking Mechanism: This part is a nightmare. You really need to deaden this as much as you can to stop the loudest rattles of the entire car. Especially if you are even the very least concerned about the way your car sounds outside of the car (buzzing and rattling like a cheap import or american car). I have taken deader material, and put it on all of the moving joints. Yes, you read me right, I put deadener *IN* the moving joints for the lock. [u]***NOT THE LOCK CYLINDER WHERE THE KEY GOES***[u], but on the actuator joints on the pushrods and some other moving parts that are not inside the lock cylinder. This helped out a lot. All of the moving pieces were loose and jiggily, now they are stiff, yet still function well and move freely. Don't go apeshit and overdo the joints with golf ball sized globs on it, just a layer to cover the outside of the joint is sufficient. I've also stock some deadener around where the lock cylinder pushes on the tab that actuates the trunk's latch. Over time this will get rubbed off- but hey. Basically, anywhere that will not get *into* the lock tumbler is 'go for deadener.' On the outside of the car, the ~2 foot wide lip that goes around the trunk lock and above the license plate, take that off, and give that a good layer of deadener, especially where it adheres to the body of the car. You don't want it all over the edges so it's seeping around the trim, but you get the idea. Put deadener over where the screws mounts go to attach it to the car, this will firm up the whole thing. Now, the only thing I have found that would completely stop the lock from rattling, was grabbing a hold of the lock and applying a fairly strong upwards or downwards force on it, wedging it against its mountings. Based on that, I tried to put layers of deadener on that lip thing, on the underside of where the lock cylinder goes into the hole (foil side against the lock cylinder), so that when the lip was screwed back onto the trunk lid, it would apply a torque to the lock, and help hold it still. The deadener I used had an aluminum backing, so the cylinder could still slide in and out. For the rattles, this helped tremendously, but it definitely did not completely cease the rattle - it merely raised the bar to where it would start to rattle again. So far that's better than nothing. The downside to all of this is, some deadener will squish out, get on the cylinder, and make it difficult to push in and out. It won't completely gum it up unless you simply use way too much, but it won’t cause the lock to completely fail beyond repair - you'll just have to clean some of the crap off if it is too stiff. So far, this is the only thing I found to do any sort of good for that stupid lock. I bet the insides of the lock tumbler are also rattling about, which may be why it is so difficult to manage. I may want to try spraying a good deal of lithium grease into the cylinder, hopefully that might calm tat damn thing's insides down some, but will probably make your key messy when you use it to unlock it. I tried tightening the bolts that hold all this stuff together, and that didn't help at all.
If anyone has a better or more solution to stop the trunk lock from rattling, please speak up! Anyone with bass in their E36 knows that the lock is really quite an embarrassing noise.
Trunk Vent Flaps: On either side of the trunk, about equal in height to the black trim on the outside of the car, are two vents. These vents are flapped with lightweight and flexible rubber, so that they let air out when there's positive pressure (with your climate control blower on), and shut with neutral or negative pressure (recalculate or climate control off). So, you can bet with high intensity bass, these things flap about and make a lot of racket. On top of this, they also leak out much of the bass to the outside of the car. This decreases the efficiency and potential loudness of the bass to the inside of the cabin, and - well, leaks the bass out of the car so it will annoy people and police. I don't think you should seal them completely up though. The climate control system needs them to vent incoming air to the outside of the car, otherwise the air coming into the car has nowhere to go, and you don't get hardly any airflow from the air vents, unless you crack a window or the sunroof. If you always run with recirculation on, or never use the climate control - I guess go ahead and seal one or both of them up. Doing that should stop, or drastically decrease, the chuffing/flapping noise coming from both sides of the back of the car. it would also reduce the whole bumper from rattling like mad, and divert the bass that was going out of those vents - pissing everyone else off, towards the cabin where you really want it. (I mean, if you are one of those obnoxious, show-off types, and want to be a douche and 'impress' people with how you spent your money, you can still just roll your windows down.) Also to take note of, your battery has a vent tube that vents hydrogen gas though a hole in the trunk floor. Before you decide to seal those flappy vents up - Please double check that the vent tube IS in fact there, is not obstructed, is hooked up to the battery correctly, and venting though that hole to the outside. Lead Acid batteries off-gas hydrogen when discharging and charging (so when current is flowing through them) and as you should know, hydrogen gas is kinda.... well, Really Fucking Flammable. It's also corrosive and will help accelerate the rusting-out of your car. I have not sealed my flappy vents up because I really want as much airflow as I can get, which can still be on the weak side even with a fresh micro filter, so I don't want to diminish it any further if I can help it.
Rear Bumper: Because of the vent flappy guys, the plastic bumper is immediately in the path of the bass coming from the vents, since it’s not that stiff and light enough, it will also vibrate. The heat shielding from the exhaust will also vibrate, and any sand or pebbles stuck in the bumper/heat shielding will also rattle. There is not too much that I've found you can do to stop it, except sort-of bend the heat shielding around, away from things that it can vibrate onto so it stops rattling against stuff. You may need to shake off all the rocks and such that are stuck up on it also. I guess you could somehow try to attach it to the very top corners of it to the fender wells using some sort of screw and clamp. but I'm not sure how you'd accomplish that without it being visible from normal viewing angles. The metal lip that you have to screw into is extremely thin, so I'm not sure what to do here other than plug up the trunk air vents so the trunk isn't excited so much.
I'm sure there are a couple of things I've forgotten. The glove box probably has some issues, and I've done some things to that before I started shaking my car to bits, so I'm not sure about that.
More stuff to help you search down rattles:
Bass test tones (read the header for information about them) Use an ipod or burn them to CD. Maximum volume sine tones so you can set gains, and find resonances/rattles) in your car:
Let me know if there's anything I missed, any suggestions, etc. PM ME IF YOU FIND OUT HOW TO STOP THE REAR TRUNK LOCK!!!
Should I have started a new thread? I think I wrote too much...... copy-pasted into Word resulted in 10 pages, good god. .... I wasn't joking when i said I loved bass...