Sound Deadening & Cab Noise Reduction
These projects were also fired off after I decided to keep this truck. After 111,000 miles, things are pretty well loosened up engine-wise, and the truck was noisy going down the road. The noise was a combination of road noise and engine noise. So I set out on a quest to get the interior as quiet as possible. After doing some research, I determined that the best way to begin to quiet the interior was to install sound deadening/dampening insulation material. Dynamat is the name most everyone knows, but there are other alternatives out there, including B-Quiet and FatMat. I chose FatMat based on price and the recommendation of my friend Chris. He was in the car stereo business back in his pre-college days and has worked with all of the products out there. For the price, FatMat is hard to beat (and is half the cost of Dynamat). Essentially, the idea behind these products is to stop the metal on the vehicle body from resonating. Doing this will drastically reduce noise in the cab and improve the acoustics of the cab.
But let me tell you, this was a major project. Excluding the dash, the entire interior of the truck came out: seats, center console, gear shifter, overhead console trim, overhead lights, headliner, rear wall cover, door seals, all plastic trim pieces and the carpet. Everything but the dash. I started the project on a Friday afternoon and finished the following Monday afternoon. This was the first project like this that I had ever done, so I could do it faster in the future.
Oh, I forgot to mention, I did the doors the weekend previous to ripping out the interior. The four doors took me the equivalent of an entire day to do. Lots of detail work. But you need to apply the material to the interior metal skin directly under the interior door panel and also to the interior side of the exterior door skin. I was able to cover the majority of that surface by working my hands through the openings on the stamped interior metal and placing the material as far up and over as I could reach and still press it down.
I applied a single layer of FatMat to all surfaces I could put it on except for the floor. I double-layered the floor. I then applied a layer of jute on top of the FatMat from front to back. Not only does this help with sound, it also gives the carpet a nice plush, squishy feeling. I secured the jute to the FatMat using some 3M Super 77 spray adhesive.
Since I had some extra FatMat material available, I applied it to the back of the fuse panel cover and to the back side of the glove compartment door.
Since everything was out, including the carpet, it was a good time to do some cleaning. After taking the carpet out, I whipped out the pressure washer and gave the carpet a good cleaning on both sides. It dried in the sun (and with the help of a box fan) for almost two whole days. It was dry when we put it back in Sunday night.
Other sound deadening I did while the interior was out:
- Rear posts, posts between front/rear doors, rear roof support member, support member below back window: There are some holes large enough to stuff with fiberglass insulation. I stuffed them as full as I could, leaving enough space to fill the remainder with expanding foam
- Expanding foam: You have to be extremely careful - and most importantly, patient - when working with this stuff in your vehicle. I've heard horror stories of folks using this foam only to have the stuff expand so much as to cause the exterior metal to bow up/out. The stuff needs a place to expand. If it doesn't have it, it will make it! I applied 6 cans of this foam to my interior: A pillars, roof support beams, posts, just about anywhere there was space - and holes for the stuff to expand out of. Let it expand, and then break off or cut/trim the stuff. Do this early and often, as the unexpanded foam will continue to seep and expand out of some holes. Give it a place to go! I applied the stuff late Saturday evening, worked with it for a little bit, then went to bed and let it dry overnight. Some of the spots were still oozing and expanding Sunday night, but it was finished oozing by Monday morning. Before reinstalling all of the finish trim and everything, I did one final trimming. No bowing problems at all.
These projects made a HUGE impact on interior noise while driving. Road noise has been drastically reduced, engine noise was reduced somewhat, and the stock stereo system sounds way better. I know a vast improvement had been made when I had to turn down the volume on my Bluetooth phone earpiece from maximum. Callers on the other end of the call also noticed a reduction in ambient noise while I was driving.
Here are some pictures of the project in progress:
But it still wasn't enough. There was still some road noise, and the engine noise was still pretty loud.
Door Seal Modification
After surfing around on TheDieselStop.com's forums, I found a couple of other ideas. First, there is a modification you can do to the door seals. This mod involves fishing 3/8" outside diameter vinyl or silicone tubing through the hollow portion of the door seal. This in effect makes a tighter seal between the door and the body, thereby reducing road and wind noise. I was skeptical about it being effective, but it made a pretty big difference. And it was a low-cost modification. I bought 60 feet of tubing at $0.20 per foot at Lowe's, so it was a whole $12 for the tubing. I used about 54 or 55 feet of it to modify all 4 doors. Easy, cheap and effective. The only thing is, the driver's door is a little stiff when closing. You have to give it a little extra oomph when closing it to get it to completely latch. The other three doors close with no extra force required.
Excursion Sound Panels
The front portion of a Super Duty truck's cab and the cab of an Excursion are virtually identical. Since the Excursion is geared more as an SUV and luxury vehicle, they did more sound deadening. One of the sound deadening tricks they used was to install a plastic panel backed with jute in the empty space between the dash and the firewall, essentially closing the big gaping hole there (and there's a huge one under the driver's side and a smaller on on the passenger side).
Since the cabs are virtually identical, those Excursion sound panels will fit 99 and up Super Duty trucks. The passenger side panel is a direct bolt-on install. The driver's side, on the other hand, took a little southern engineering - especially on my truck. All Excursions have automatic transmissions - my truck is a manual, and there was no cut-out in the panel for the clutch pedal. No problem - an air saw to cut the panel and a razor to cut the jute, and it fit right in. Well, almost. Apparently, the bottom portion of the Excursion dash is a little different than the Super Duty dash, and while it does attach to the firewall by the accelerator pedal and to the computer mounting bracket, there was no place to attach it to the bottom of the dash. Enter the zippie ties. A little creativity with zip ties, and it was mounted with no problem.
For those that are interested, here are the Ford part numbers:
YC3Z-78046A24-AA - Passenger Side
YC3Z-78046A25-AA - Driver's Side
I bought the panels from fordpartsonline.com, and with shipping, they were $71.47 total. I really think they made a difference since they help block the sound coming through the firewall and under the openings in the dash.
Hood Liner
My friend Chris helped me install a Dynamat hood liner. This project involved removing the entire hood from its hinges. Due to the contoured design of the metal on the hood's underside, we didn't cover everything. We made templates so we could cut the hood liner material to fit in the six depressions. Before installing, though, we degreased the entire hood and applied FatMat in the depressions. We also sealed the support cross members with silicone. There was not enough material left over to do a second layer all the way across the hood, so maybe at some point down the road I will buy another kit and use it as a replacement for the factory hood liner (which we were able to reinstall). I really believe, though, that this mod made a pretty significant difference in engine noise. I didn't have my camera with me when I was installing the liner, but if I go back and add a second layer, I'll take pictures of the first layer before adding the second.
Future Sound Dampening Mods
I haven't made up my mind yet if I'll do these or not, but I have been considering them:
- Add second hood liner layer
- Pull the dash and apply FatMat and jute directly to the interior side of the firewall
- UPDATE 4/21/07: Further research has lead me to believe this would likely be too much work for too little gain. I may remove some of the dash panels and apply jute (and maybe some FatMat) to the undersides of them where it will fit, but there seems to be too much "stuff" along the firewall (ducting, etc.) to make this a worthwhile effort.
- Fuel system modifications: I know this sounds like it should go under the engine/drivetrain section, but quite a few people say that several fuel system mods can reduce engine noise. The stock fuel lines and the way they're connected introduce a fair amount of air into the fuel stream. This makes the injectors noisy. Supposedly, by reducing and/or eliminating the amount of air in the fuel, the injectors will be more quiet, thereby reducing engine noise, cackle, etc.
- ThermoTec Exhaust Insulating Wrap: this idea was proposed in a post I made about reducing engine noise on TheDieselStop.com. It was suggested as a way to reduce exhaust noise. Might be worth further investigation.
One thing I will definitely do, though, is add a second layer of jute to the floor when I pull the interior again to run the wiring for the stereo system I will be installing. I may also apply a layer of jute to the back wall under the rear window as well.